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A357968
Expansion of e.g.f. exp( x * (exp(x^4) - 1) ).
2
1, 0, 0, 0, 0, 120, 0, 0, 0, 181440, 1814400, 0, 0, 1037836800, 43589145600, 217945728000, 0, 14820309504000, 1867358997504000, 30411275102208000, 101370917007360000, 425757851430912000, 140500090972200960000, 5385836820601036800000
OFFSET
0,6
FORMULA
a(n) = n! * Sum_{k=0..floor(n/4)} Stirling2(k,n-4*k)/k!.
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x*(exp(x^4)-1))))
(PARI) a(n) = n!*sum(k=0, n\4, stirling(k, n-4*k, 2)/k!);
CROSSREFS
Sequence in context: A196429 A243779 A267335 * A156415 A073836 A242836
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 22 2022
STATUS
approved