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.

A218261 E.g.f.: Sum_{n>=0} Product_{k=1..n} (exp((2*k-1)*x) - 1) / (2*k-1).

Original entry on oeis.org

1, 1, 3, 19, 191, 2731, 52063, 1264747, 37912143, 1368247627, 58312623743, 2889264152875, 164299982895535, 10607439707069323, 770371122097072863, 62438253016068932203, 5608567981763102915087, 554952834214350689736139, 60161153106358242206145343
Offset: 0

Views

Author

Paul D. Hanna, Oct 24 2012

Keywords

Examples

			E.g.f.: A(x) = 1 + x + 3*x^2/2! + 19*x^3/3! + 191*x^4/4! + 2731*x^5/5! +...
where
A(x) = 1 + (exp(x)-1) + (exp(x)-1)*(exp(3*x)-1)/(1*3) + (exp(x)-1)*(exp(3*x)-1)*(exp(5*x)-1)/(1*3*5) + (exp(x)-1)*(exp(3*x)-1)*(exp(5*x)-1)*(exp(7*x)-1)/(1*3*5*7) +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(X=x+x*O(x^n),Egf);Egf=sum(m=0,n,prod(k=1,m,(exp((2*k-1)*X)-1)/(2*k-1)));n!*polcoeff(Egf,n)}
    for(n=0,30,print1(a(n),", "))