A009767 Expansion of tan(tanh(x))*sin(x)/2.

1, 120, 241920, 2352430080, 70008319180800, 4981141593037209600, 724337282211580477440000, 193082117289145211195228160000, 87097726450270042926290105794560000

Offset

0,2

Links

Table of n, a(n) for n=0..8.

Mathematica

Tan[ x^2 ]/2 (* [ x^(4n+2) ] *)

Crossrefs

A024348.

Sequence in context: A172805 A008701 A158043 * A181750 A003789 A325024

Adjacent sequences: A009764 A009765 A009766 * A009768 A009769 A009770

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested 03/97.

Status

approved