A012499 Expansion of e.g.f. tan(cos(x)*arctan(x)) (odd powers only).

1, -3, -35, 1729, -12711, -5819099, 581423349, 26066838953, -19485197470415, 2379630157273805, 789057561743200397, -445703452244142678255, 25928070972710765150345, 80008658408138506870433013, -41780425117352684596856468827, -7585811803346771885529485351175, 23110904483392454783722911793216609

Offset

0,2

Links

Table of n, a(n) for n=0..16.

Example

x - 3/3!*x^3 - 35/5!*x^5 + 1729/7!*x^7 - 12711/9!*x^9 ...

Prog

(PARI) my(x='x+O('x^40), v=Vec(serlaplace(tan(cos(x)*atan(x))))); vector(#v\2, k, v[2*k-1]) \\ Michel Marcus, Mar 11 2025

Crossrefs

Sequence in context: A136556 A006098 A320845 * A125530 A334253 A068726

Adjacent sequences: A012496 A012497 A012498 * A012500 A012501 A012502

Keyword

sign

Author

Patrick Demichel

Extensions

More terms from Michel Marcus, Mar 11 2025

Status

approved