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A349889
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a(n) = Sum_{k=0..n} (-1)^(n-k) * k^(2*n).
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3
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1, 1, 15, 666, 59230, 8775075, 1948891581, 605698755508, 250914820143996, 133610836793706405, 88919025666286620475, 72317513878698256697166, 70571883548815735717843290, 81383769918571603591381635271
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OFFSET
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0,3
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LINKS
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Table of n, a(n) for n=0..13.
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FORMULA
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G.f.: Sum_{k>=0} (k^2 * x)^k/(1 + k^2 * x).
a(n) ~ 1/(1 + exp(-2)) * n^(2*n). - Vaclav Kotesovec, Dec 10 2021
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PROG
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(PARI) a(n) = sum(k=0, n, (-1)^(n-k)*k^(2*n));
(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (k^2*x)^k/(1+k^2*x)))
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CROSSREFS
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Cf. A120485, A249459, A349884, A349891, A349902.
Sequence in context: A280179 A223203 A279465 * A279531 A079600 A171113
Adjacent sequences: A349886 A349887 A349888 * A349890 A349891 A349892
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KEYWORD
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nonn
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AUTHOR
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Seiichi Manyama, Dec 04 2021
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STATUS
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approved
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