This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A009798 E.g.f. tanh(sin(x)*cos(x)) (odd powers only). 1
 1, -6, 112, -5488, 451840, -57057792, 10262228992, -2484525168640, 779280513040384, -307370299649556480, 148889329569589362688, -86890528715348714192896, 60129120979379216762011648 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(n):=(-1)^n*sum(k=0..n, 4^(n-k)/(2*k+1)!*sum(i=0..2*k+1, (-1)^i*(2*k+1-2*i)^(2*n+1)*binomial(2*k+1, i))*(sum(j=1..2*k+1, j!*2^(-j)*(-1)^(k+1+j)*stirling2(2*k+1, j)))). - Vladimir Kruchinin, Jun 29 2011 PROG (Maxima) a(n):=(-1)^n*sum(4^(n-k)/(2*k+1)!*sum((-1)^i*(2*k+1-2*i)^(2*n+1)*binomial(2*k+1, i), i, 0, 2*k+1)*(sum(j!*2^(-j)*(-1)^(k+1+j)*stirling2(2*k+1, j), j, 1, 2*k+1)), k, 0, n); /* Vladimir Kruchinin, Jun 28 2011 */ CROSSREFS Cf. A101921. Sequence in context: A162081 A296949 A009612 * A088668 A275924 A288561 Adjacent sequences:  A009795 A009796 A009797 * A009799 A009800 A009801 KEYWORD sign AUTHOR EXTENSIONS Extended with signs by Olivier Gérard, Mar 15 1997 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 20 23:39 EDT 2018. Contains 316405 sequences. (Running on oeis4.)