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A024343 Expansion of e.g.f. sin(x^2), coefficients of x^(4*n + 2). 2
2, -120, 30240, -17297280, 17643225600, -28158588057600, 64764752532480000, -202843204931727360000, 830034394580628357120000, -4299578163927654889881600000, 27500101936481280675682713600000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Absolute values are coefficients of expansion of sinh(x^2).

LINKS

Table of n, a(n) for n=0..10.

FORMULA

(-1)^n * (4n+2)! / (2n+1)!.

E.g.f.: Sin[ x^2 ] (* [ x^(4n+2) ] *)

a(n) = 2 * A009564(n). - Sean A. Irvine, Jul 01 2019

PROG

(PARI) a(n)=polcoeff(serlaplace(sin(x^2)), 4*n+2)

(PARI) a(n)=(-1)^n*(4*n+2)!/(2*n+1)!

CROSSREFS

Bisection of A001813.

Sequence in context: A077540 A272180 A187880 * A100043 A181760 A290247

Adjacent sequences:  A024340 A024341 A024342 * A024344 A024345 A024346

KEYWORD

sign

AUTHOR

R. H. Hardin

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

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Last modified October 17 14:23 EDT 2019. Contains 328113 sequences. (Running on oeis4.)