OFFSET
0,7
LINKS
G. Nebe, E. M. Rains and N. J. A. Sloane, Self-Dual Codes and Invariant Theory, Springer, Berlin, 2006.
Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,-1).
FORMULA
Molien series is 1/((1-x^2)*(1-x^12)).
a(n)=1+floor(n/6)
a(n)=1+(6*n-15+3*(-1)^n+12*sin[(2*n+1)*Pi/6]+4*sqrt(3)*sin[(2*n+1)*Pi/3])/36
MATHEMATICA
CoefficientList[Series[1/((1-x)(1-x^6)), {x, 0, 90}], x] (* or *) LinearRecurrence[{1, 0, 0, 0, 0, 1, -1}, {1, 1, 1, 1, 1, 1, 2}, 90] (* Harvey P. Dale, Oct 29 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 07 2004
STATUS
approved