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A014696 Poincaré series [or Poincare series] (or Molien series) for mod 2 cohomology of universal W-group W(3). 0
1, 3, 14, 30, 77, 138, 273, 438, 748, 1113, 1729, 2436, 3542, 4788, 6630, 8676, 11571, 14751, 19096, 23826, 30107, 36894, 45695, 55146, 67158, 79989, 96019, 113064, 134044, 156264, 183260, 211752, 245973, 281979, 324786, 369702, 422617, 478002 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..37.

A. Adem, Recent developments in the cohomology of finite groups, Notices Amer. Math. Soc., 44 (1997), 806-812.

Index entries for two-way infinite sequences

Index entries for linear recurrences with constant coefficients, signature (2,3,-8,-2,12,-2,-8,3,2,-1).

FORMULA

G.f.: (1+x+5x^2+x^3+x^4)/((1-x)^2*(1-x^2)^4). a(n)=-a(-6-n).

MAPLE

(x^4+x^3+5*x^2+x+1)/(x-1)^2/(-1+x^2)^4;

MATHEMATICA

LinearRecurrence[{2, 3, -8, -2, 12, -2, -8, 3, 2, -1}, {1, 3, 14, 30, 77, 138, 273, 438, 748, 1113}, 40] (* Harvey P. Dale, Sep 24 2017 *)

PROG

(PARI) a(n)=n+=3; n*((18*n^4-70*n^2+97)-(50*n^2-95)*(-1)^n)/3840

CROSSREFS

Sequence in context: A256053 A354041 A031049 * A235137 A197944 A071396

Adjacent sequences:  A014693 A014694 A014695 * A014697 A014698 A014699

KEYWORD

nonn,easy

AUTHOR

Alejandro Adem (adem(AT)math.wisc.edu)

STATUS

approved

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Last modified May 20 06:34 EDT 2022. Contains 353852 sequences. (Running on oeis4.)