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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 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 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 February 26 20:23 EST 2020. Contains 332295 sequences. (Running on oeis4.)