Solving The Recurrence A S = ∑ I = 0 S − 1 Α I ( S ) A I A_{s}=\sum_{i=0}^{s-1}\alpha_i{(s)}\ A_i A S ​ = ∑ I = 0 S − 1 ​ Α I ​ ( S ) A I ​ , Where A 0 = 1 A_0=1 A 0 ​ = 1 .

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Introduction

In this article, we will delve into the world of recurrence relations and explore a specific recurrence relation that has been discovered while researching the Bessel numbers sequence. The Bessel numbers sequence, also known as A001498 in the Online Encyclopedia of Integer Sequences (OEIS), has been extensively studied in various mathematical contexts. However, a different recurrence relation for these numbers has been found, which is not mentioned in any of the existing references. In this article, we will derive the solution to this recurrence relation and provide a detailed analysis of its properties.

The Recurrence Relation

The recurrence relation in question is given by:

as=i=0s1αi(s) aia_{s}=\sum_{i=0}^{s-1}\alpha_i{(s)}\ a_i

where a0=1a_0=1. This relation is a type of linear recurrence relation, where each term asa_s is expressed as a linear combination of previous terms aia_i. The coefficients αi(s)\alpha_i(s) are functions of the index ss and are not explicitly given.

Derivation of the Solution

To solve this recurrence relation, we can use the method of generating functions. We start by defining the generating function for the sequence asa_s as:

A(x)=s=0asxsA(x) = \sum_{s=0}^{\infty} a_s x^s

Using the recurrence relation, we can express A(x)A(x) in terms of itself:

A(x)=a0+s=1(i=0s1αi(s)ai)xsA(x) = a_0 + \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_i \right) x^s

We can rewrite the inner sum as:

i=0s1αi(s)ai=i=0s1αi(s)j=0ajxj\sum_{i=0}^{s-1} \alpha_i(s) a_i = \sum_{i=0}^{s-1} \alpha_i(s) \sum_{j=0}^{\infty} a_j x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

i=0s1αi(s)ai=j=0(i=0s1αi(s)aj)xj\sum_{i=0}^{s-1} \alpha_i(s) a_i = \sum_{j=0}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+s=1(j=0(i=0s1αi(s)aj)xj)xsA(x) = 1 + \sum_{s=1}^{\infty} \left( \sum_{j=0}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^j \right) x^s

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Q: What is the recurrence relation as=i=0s1αi(s) aia_{s}=\sum_{i=0}^{s-1}\alpha_i{(s)}\ a_i, where a0=1a_0=1?

A: The recurrence relation is a type of linear recurrence relation, where each term asa_s is expressed as a linear combination of previous terms aia_i. The coefficients αi(s)\alpha_i(s) are functions of the index ss and are not explicitly given.

Q: How do you derive the solution to the recurrence relation?

A: To derive the solution, we can use the method of generating functions. We start by defining the generating function for the sequence asa_s as:

A(x)=s=0asxsA(x) = \sum_{s=0}^{\infty} a_s x^s

Using the recurrence relation, we can express A(x)A(x) in terms of itself:

A(x)=1+s=1(i=0s1αi(s)ai)xsA(x) = 1 + \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_i \right) x^s

We can rewrite the inner sum as:

i=0s1αi(s)ai=j=0(i=0s1αi(s)aj)xj\sum_{i=0}^{s-1} \alpha_i(s) a_i = \sum_{j=0}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

i=0s1αi(s)ai=j=0(i=0s1αi(s)aj)xj\sum_{i=0}^{s-1} \alpha_i(s) a_i = \sum_{j=0}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0sαi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Using the fact that a0=1a_0=1, we can simplify the expression:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

Now, we can express A(x)A(x) in terms of itself:

A(x)=1+j=0(s=1(i=0s1αi(s)aj)xs)xjA(x) = 1 + \sum_{j=0}^{\infty} \left( \sum_{s=1}^{\infty} \left( \sum_{i=0}^{s-1} \alpha_i(s) a_j \right) x^s \right) x^j

We can rewrite the expression as:

A(x) = 1 + \sum_{j