A009516 Expansion of sin(tan(x)/cos(x)).

1, 4, 12, -1472, -159792, -16362304, -1834702400, -218477736448, -23399883425536, -225490426670080, 1498513205985651712, 985137918553296764928, 536781621147089121005568, 285950922368074600238661632

Offset

0,2

Links

Table of n, a(n) for n=0..13.

Mathematica

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

Prog

(Maxima)
a(n):=4*sum(((-1)^(m)*sum((binomial(m+k-1, 2*m)*sum((2*i-2*k+1)^(2*n+1)*binomial(2*k-1, i)*(-1)^(i-n+k), i, 0, k-1/2))/2^(2*k), k, m+1, n+1))/(2*m+1)!, m, 0, n); /* Vladimir Kruchinin, Jun 23 2011 */

Crossrefs

Sequence in context: A085116 A104129 A144631 * A266500 A146210 A024248

Adjacent sequences: A009513 A009514 A009515 * A009517 A009518 A009519

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved