A009570 Expansion of e.g.f. sinh(log(1+tanh(x))).

0, 1, -1, 1, -4, 16, -16, -104, -64, 4096, -256, -176384, -1024, 11186176, -4096, -951870464, -16384, 104932704256, -65536, -14544442425344, -262144, 2475749027086336, -1048576, -507711943251329024, -4194304, 123460740095112380416, -16777216

Offset

0,5

Links

G. C. Greubel, Table of n, a(n) for n = 0..450

Formula

E.g.f.: (1/Q(0)-Q(0))/2, where Q(k) = 1 - x/( 2*k+1 + x/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Dec 20 2013

Mathematica

With[{nmax = 50}, CoefficientList[Series[Sinh[Log[1 + Tanh[x]]], {x, 0, nmax}], x]*Range[0, nmax]!] (* G. C. Greubel, Jan 21 2018 *)

Prog

(PARI) x='x+O('x^30); concat([0], Vec(serlaplace( sin(log(1+tanh(x)))))) \\ G. C. Greubel, Jan 21 2018

Crossrefs

Cf. A009126.

Sequence in context: A223585 A202680 A263568 * A232839 A140299 A119007

Adjacent sequences: A009567 A009568 A009569 * A009571 A009572 A009573

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved