cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A091773 G.f.: Product((1+x^i)/(1-x^i),i=1..n-1)/(1-x^n), with n = 5.

Original entry on oeis.org

1, 2, 4, 8, 14, 23, 36, 54, 78, 110, 151, 202, 266, 344, 438, 551, 684, 840, 1022, 1232, 1473, 1748, 2060, 2412, 2808, 3251, 3744, 4292, 4898, 5566, 6301, 7106, 7986, 8946, 9990, 11123, 12350, 13676, 15106, 16646, 18301, 20076, 21978, 24012, 26184, 28501, 30968
Offset: 0

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Author

N. J. A. Sloane, Mar 18 2004

Keywords

Comments

Poincaré series [or Poincare series] (or Molien series) for H^*(O_5(q); F_2).

References

  • A. Adem and R. J. Milgram, Cohomology of Finite Groups, Springer-Verlag, 2nd. ed., 2004; p. 233.

Programs

  • Mathematica
    LinearRecurrence[{3,-3,2,-3,4,-4,3,-2,3,-3,1},{1,2,4,8,14,23,36,54,78,110,151},50] (* Harvey P. Dale, Feb 17 2018 *)

Formula

G.f.: -(x^2-x+1)*(x^4+1) / ((x-1)^5*(x^2+x+1)*(x^4+x^3+x^2+x+1)). - Colin Barker, Jan 31 2013
a(n) = 3*a(n-1)-3*a(n-2)+2*a(n-3)-3*a(n-4)+4*a(n-5)-4*a(n-6)+3*a(n-7)-2*a(n-8)+3*a(n-9)-3*a(n-10)+a(n-11). - Wesley Ivan Hurt, Apr 26 2021