OFFSET
0,1
COMMENTS
Absolute values are coefficients of expansion of sinh(x^2).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..175
FORMULA
a(n) = (-1)^n * (4*n+2)! / (2*n+1)!.
E.g.f.: [x^(4*n+2)] sin(x^2)
a(n) = 2 * A009564(n). - Sean A. Irvine, Jul 01 2019
MATHEMATICA
Table[(-1)^n*(2*n+1)!*Binomial[4*n+2, 2*n+1], {n, 0, 30}] (* G. C. Greubel, Jan 29 2022 *)
PROG
(PARI) a(n)=polcoeff(serlaplace(sin(x^2)), 4*n+2)
(PARI) a(n)=(-1)^n*(4*n+2)!/(2*n+1)!
(Sage) f=factorial; [(-1)^n*f(4*n+2)/f(2*n+1) for n in (0..30)] # G. C. Greubel, Jan 29 2022
(Magma) F:=Factorial;; [(-1)^n*F(4*n+2)/F(2*n+1) : n in [0..30]]; // G. C. Greubel, Jan 29 2022
CROSSREFS
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Edited by Ralf Stephan, Mar 25 2004
Name edited by Michel Marcus, Jul 01 2019
STATUS
approved