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A173218
G.f.: A(x) = Sum_{n>=0} (1 + x)^(n^2+n) / 2^(n+1).
3
1, 4, 50, 1040, 30300, 1135080, 51972668, 2812429632, 175606496520, 12426817517920, 982846762742416, 85916923493646752, 8225856593959648696, 856044724445883011520, 96213518828394481754400
OFFSET
0,2
LINKS
FORMULA
a(n) ~ 2^(2*n) * n^n / (2^(log(2)/8) * log(2)^(2*n+1) * exp(n)). - Vaclav Kotesovec, Oct 08 2019
MATHEMATICA
Table[Sum[StirlingS1[n, j] * Sum[Binomial[j, s] * HurwitzLerchPhi[1/2, -j - s, 0], {s, 0, j}], {j, 0, n}] / (2*n!), {n, 0, 20}] (* Vaclav Kotesovec, Oct 08 2019 *)
PROG
(PARI) {a(n)=local(A=sum(m=0, n^2+100, (1+x +O(x^(n+2)))^(m*(m+1))/2^(m+1))); round(polcoeff(A, n))}
CROSSREFS
Sequence in context: A234870 A139087 A349655 * A234714 A201829 A201209
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 05 2010
STATUS
approved