A092508 - OEIS

A092508

G.f.: (1+x^18)/((1-x)*(1-x^4)*(1-x^8)*(1-x^12)).

1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 7, 7, 7, 7, 11, 11, 12, 12, 17, 17, 18, 18, 25, 25, 27, 27, 35, 35, 38, 38, 48, 48, 52, 52, 64, 64, 69, 69, 83, 83, 90, 90, 106, 106, 114, 114, 133, 133, 143, 143, 164, 164, 176, 176, 200, 200, 214, 214, 241, 241, 257, 257, 287, 287, 306, 306, 339

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OFFSET

0,5

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

G. Nebe, E. M. Rains and N. J. A. Sloane, Self-Dual Codes and Invariant Theory, Springer, Berlin, 2006.

Index entries for Molien series

Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1,0,0,1,-1,0,0,0,0,0,0,-1,1,0,0,-1,1,0,0,1,-1).

FORMULA

a(n) ~ 1/1152*n^3. - Ralf Stephan, Apr 29 2014

G.f.: ( 1-x^6+x^12 ) / ( (1+x+x^2)*(1-x+x^2)*(x^4+1)*(x^2+1)^2*(1+x)^3*(x-1)^4 ). - R. J. Mathar, Dec 18 2014

MATHEMATICA

CoefficientList[Series[(1+x^18)/((1-x)(1-x^4)(1-x^8)(1-x^12)), {x, 0, 100}], x] (* Harvey P. Dale, Dec 24 2019 *)

PROG

(PARI) a(n)=round((2*n^3+(21+3*(-1)^n)*n^2+(447+21*(-1)^n+108*(-1)^(n\2))*n+1393+223*(-1)^n)/2304) \\ Tani Akinari, May 30 2014

CROSSREFS

Sequence in context: A092533 A092532 A073504 * A032544 A200675 A029079

Adjacent sequences: A092505 A092506 A092507 * A092509 A092510 A092511

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Apr 09 2004

STATUS

approved