A293020 a(n) = n! * [x^n] exp(n*tan(x)).

1, 1, 4, 33, 384, 5705, 103392, 2213225, 54648832, 1529006769, 47806489600, 1651929898641, 62514008358912, 2571311967708601, 114219516618117120, 5449390043986849305, 277913379747357786112, 15087434965491213149153, 868698417435317196816384, 52875073161897308106963585

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Formula

a(n) ~ c * d^n * n^n / exp(n), where d = 3.2897906634948022290195938576166779380... and c = 0.7144692216716261155107169918... - Vaclav Kotesovec, Oct 06 2017

Mathematica

Table[n! SeriesCoefficient[Exp[n Tan[x]], {x, 0, n}], {n, 0, 19}]

Crossrefs

Cf. A006229, A133941.

Sequence in context: A187738 A198900 A166906 * A293193 A295256 A269926

Adjacent sequences: A293017 A293018 A293019 * A293021 A293022 A293023

Keyword

nonn

Author

Ilya Gutkovskiy, Sep 28 2017

Status

approved