A215681 n-th derivative of sech(x)^tan(x) at x=0.

1, 0, 0, -3, 0, -10, 90, -308, 1680, -13560, 123480, -788568, 7646760, -76432720, 841320480, -8436217208, 103473901440, -1320024546240, 17546621595840, -235942960528128, 3481689023521920, -54132188358133120, 858287202343992960, -14187715233218409728

Offset

0,4

Comments

sech(x) = 1/cosh(x).

Links

Table of n, a(n) for n=0..23.

Formula

E.g.f.: sech(x)^tan(x).

Maple

a:= n-> n!* coeff(series(sech(x)^tan(x), x, n+1), x, n):
seq (a(n), n=0..25);  # Alois P. Heinz, Aug 20 2012

Mathematica

f[x_] := Sech[x]^Tan[x]; Table[Derivative[n][f][0], {n, 0, 25}]

Crossrefs

Cf. A215585, A215587.

Sequence in context: A186247 A215585 A215682 * A215587 A094897 A252096

Adjacent sequences: A215678 A215679 A215680 * A215682 A215683 A215684

Keyword

sign

Author

Michel Lagneau, Aug 20 2012

Status

approved