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A326718
a(n) = n! * [x^n] (tanh(x) + x*(2*x*tanh(x) - 1)*sech(x)^2)/8.
1
0, 0, 0, 2, 0, -48, 0, 1632, 0, -79360, 0, 5306880, 0, -469733376, 0, 53305204736, 0, -7555152347136, 0, 1308999830077440, 0, -272332392921825280, 0, 67017976509452255232, 0, -19259875454836222722048, 0, 6392895745958900349796352, 0, -2427514339720007773354721280
OFFSET
0,4
FORMULA
E.g.f.:
MAPLE
egf := (tanh(x) + x*(2*x*tanh(x) - 1)*sech(x)^2)/8; ser := series(egf, x, 30):
seq(n!*coeff(ser, x, n), n=0..29);
CROSSREFS
a(n) = A326722(n, 4) for n >= 0.
Sequence in context: A303396 A319113 A158194 * A375415 A097173 A009493
KEYWORD
sign
AUTHOR
Peter Luschny, Aug 09 2019
STATUS
approved