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A248657 E.g.f.: Sum_{n>=0} exp(n^2*(n+1)/2*x) / (1 + exp(n^2*x))^(n+1)  =  Sum_{n>=0} a(n) * x^(2*n) / (2*n)!. 1
1, -154, 22885622, -67465813019194, 1437168237462688869782, -134874257420380161852790174234, 41492847795963159872255018412799196342, -34364863511758593932657779153553482763524487674, 66563566600887661498498837311669792149014849464660729302 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Compare to an e.g.f. of A248656: Sum_{n>=0} exp(n*(n+1)/2*x)/(1 + exp(n*x))^(n+1).

LINKS

Table of n, a(n) for n=0..8.

EXAMPLE

E.g.f.: A(x) = 1 - 154*x^2/2! + 22885622*x^4/4! - 67465813019194*x^6/6! +-...

where

A(x) = 1/2 + exp(x)/(1+exp(x))^2 + exp(6*x)/(1+exp(4*x))^3 + exp(18*x)/(1+exp(9*x))^4 + exp(40*x)/(1+exp(16*x))^5 + exp(75*x)/(1+exp(25*x))^6 +...

PROG

(PARI) \p200 \\ set precision

{A=Vec(serlaplace(sum(n=0, 800, 1.*exp(n^2*(n+1)/2*x +O(x^31))/(1 + exp(n^2*x +O(x^31)))^(n+1)) ))}

for(n=1, #A\2, print1(round(A[2*n-1]), ", "))

CROSSREFS

Cf. A248656.

Sequence in context: A227977 A282557 A200709 * A159258 A214472 A259379

Adjacent sequences:  A248654 A248655 A248656 * A248658 A248659 A248660

KEYWORD

sign

AUTHOR

Paul D. Hanna, Oct 26 2014

STATUS

approved

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Last modified October 25 22:20 EDT 2021. Contains 348256 sequences. (Running on oeis4.)