OFFSET
0,2
LINKS
Robert Israel, Table of n, a(n) for n = 0..250
FORMULA
a(n) = 2*A024225(n). [Martin Ettl, Nov 08 2012]
a(n) = (2*n)!*[x^(2*n)] tan(sin(x))*x. - Robert Israel, Mar 11 2019
MAPLE
S:= series(x*tan(sin(x)), x, 61):
seq(n!*coeff(S, x, n), n=0..60, 2); # Robert Israel, Mar 11 2019
MATHEMATICA
nn = 30; t = Range[0, nn]! CoefficientList[Series[Tan[Sin[x]]*x, {x, 0, nn}], x]; Take[t, {1, nn, 2}] (* T. D. Noe, Nov 08 2012 *)
CROSSREFS
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved