A012457 sin(arctan(x)^2)=2/2!*x^2-16/4!*x^4+248/6!*x^6-3456/8!*x^8...

2, -16, 248, -3456, -406368, 123982080, -31807263360, 9173875200000, -3114459024453120, 1251070155460915200, -591321674803999426560, 326012628782956574638080, -207713640106463567695994880

Offset

0,1

Links

Robert Israel, Table of n, a(n) for n = 0..223

Formula

Sum_{n>=0} a(n) x^(2*n+2)/(2*n+2)! = sin(arctan(x)^2). - Robert Israel, Apr 04 2016

Maple

S:= series(g, x, 52):
seq(coeff(S, x, 2*j)*(2*j)!, j=1..25); # Robert Israel, Apr 04 2016

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sin[ArcTan[x]^2], {x, 0, nn}], x] Range[0, nn]!, {3, -1, 2}]] (* Harvey P. Dale, Aug 20 2014 *)

Crossrefs

Sequence in context: A009233 A188560 A012462 * A138764 A009833 A009044

Adjacent sequences: A012454 A012455 A012456 * A012458 A012459 A012460

Keyword

sign

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Extensions

Definition clarified by Harvey P. Dale, Aug 20 2014

Status

approved