cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A158259 L.g.f.: exp(Sum_{n>=1} a(n)*x^n/n) = 1 + x*exp(Sum_{n>=1} C(2n-1,n)*a(n)*x^n/n) where C(2n-1,n) = A001700(n-1).

Original entry on oeis.org

1, 1, 4, 53, 2321, 351010, 189198136, 371045084781, 2686134761118382, 72555484959298332681, 7372783651816395650943931, 2836907736669733620359204710274, 4155363917021399525198623243750199333
Offset: 0

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Author

Paul D. Hanna, Mar 28 2009

Keywords

Examples

			L.g.f.: A(x) = x + 1*x^2/2 + 4*x^3/3 + 53*x^4/4 + 2321*x^5/5 +...
exp(A(x)) = 1 + x + 2*x^2 + 15*x^3 + 479*x^4 + 58981*x^5 +...
exp(A(x)) = 1 + x*G(x) where G(x) is the g.f. of A158109 such that:
log(G(x)) = x + 3*1*x^2/2 + 10*4*x^3/3 + 35*53*x^4/4 + 126*2321*x^5/5 +...
		

Crossrefs

Cf. A158109, A158258 (variant), A001700.

Programs

  • PARI
    {a(n)=local(A=x+x^2);if(n==0,1,for(i=1,n-1,A=log(1+x*exp(sum(m=1,n,binomial(2*m-1,m)*x^m*polcoeff(A+x*O(x^m),m) )+x*O(x^n))));n*polcoeff(A,n))}

Formula

L.g.f.: exp(Sum_{n>=1} a(n)*x^n/n) = 1 + x*G(x) where G(x) = g.f. of A158109.
exp(Sum_{n>=1} a(n)*x^n/n) = [1 + Sum_{n>=1} C(2n-1,n)*a(n)*x^n]/[1 + Sum_{n>=1} (C(2n-1,n)-1)*a(n)*x^n].
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