A003722 E.g.f. sin(sinh(x)) (odd powers only).

1, 0, -8, -56, 64, 12672, 309376, 2917888, -163782656, -12716052480, -495644917760, -4004259037184, 1359174582304768, 153146435763437568, 9620207941273255936, 142966118908253962240, -62984506636368191946752

Offset: 0

Author

R. H. Hardin, Simon Plouffe

Keywords

• sign

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..100

Programs

Mathematica

With[{nn = 50}, Take[CoefficientList[Series[Sin[Sinh[x]], {x, 0, nn}], x] Range[0, nn - 1]!, {2, -1, 2}]] (* Vincenzo Librandi, Apr 11 2014 *)

Maxima

a(n):=sum((sum((-1)^(i+j-1)*(2*j-1-2*i)^(2*n+1)*binomial(2*j-1,i),i,0,2*j-1))/(2^(2*j-1)*(2*j-1)!),j,1,n+1); /* Vladimir Kruchinin, Jun 09 2011 */

Formula

a(n) = sum(j=1..n+1, (sum(i=0..2*j-1, (-1)^(i+j-1)*(2*j-1-2*i)^(2*n+1)*binomial(2*j-1,i)))/(2^(2*j-1)*(2*j-1)!)); [Vladimir Kruchinin, Jun 09 2011]