A277500 E.g.f.: -LambertW(-tan(x)).

0, 1, 2, 11, 80, 821, 10608, 167215, 3105024, 66433129, 1609025024, 43521156755, 1300287942656, 42528924900125, 1511407185512448, 57992816331075511, 2389444376908726272, 105219795048784564945, 4931495123285481881600, 245105773365008603770907

Offset

0,3

Links

Robert Israel, Table of n, a(n) for n = 0..384

Formula

a(n) ~ sqrt(1+exp(-2)) * arctan(exp(-1))^(1/2-n) * exp(1/2-n) * n^(n-1).

Maple

S:= series(-LambertW(-tan(x)), x, 31):
seq(coeff(S, x, n)*n!, n=0..30); # Robert Israel, Mar 09 2017

Mathematica

CoefficientList[Series[-LambertW[-Tan[x]], {x, 0, 20}], x] * Range[0, 20]!

Prog

(PARI) x='x+O('x^50); concat([0], Vec(serlaplace(-lambertw(-tan(x))))) \\ G. C. Greubel, Nov 07 2017

Crossrefs

Cf. A277479, A277467, A277498, A277501.

Sequence in context: A118969 A181068 A056846 * A197718 A359222 A309417

Adjacent sequences: A277497 A277498 A277499 * A277501 A277502 A277503

Keyword

nonn

Author

Vaclav Kotesovec, Oct 18 2016

Status

approved