A009530 Expansion of e.g.f. sin(tanh(x)/cos(x)).

1, 0, 12, -336, -2096, -1043328, -29488704, -8894706432, -389860902656, -170568226222080, -6327905330549760, -6080018829202427904, 242897035394043301888, -323994054628796940582912, 123697309877515731773669376, -13142696592417683099946516480

Offset

0,3

Comments

Among solutions to a(n)=2n are primes, twice primes (A001747) and also further numbers.

Links

Table of n, a(n) for n=0..15.

Mathematica

Sin[ Tanh[ x ]/Cos[ x ] ] (* Odd Part *)

Prog

(PARI) x='x+O('x^34); v = Vec(serlaplace(sin(tanh(x)/cos(x)))); vector(#v\2, n, v[2*n-1]) \\ Michel Marcus, Apr 02 2017

Crossrefs

Sequence in context: A110101 A185247 A368771 * A159363 A009680 A218820

Adjacent sequences: A009527 A009528 A009529 * A009531 A009532 A009533

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved