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A357663
Expansion of e.g.f. cosh( (exp(4*x) - 1)/2 ).
3
1, 0, 4, 48, 464, 4480, 48448, 621824, 9320704, 154890240, 2746131456, 51237908480, 1007228375040, 20965557829632, 463091379159040, 10826828061147136, 266438312153120768, 6861616219559034880, 184128217520198123520, 5135753969867535941632
OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..floor(n/2)} 4^(n-k) * Stirling2(n,2*k).
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(cosh((exp(4*x)-1)/2)))
(PARI) a(n) = sum(k=0, n\2, 4^(n-k)*stirling(n, 2*k, 2));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 07 2022
STATUS
approved