OFFSET
0,4
LINKS
E. Bannai, S. T. Dougherty, M. Harada and M. Oura, Type II Codes, Even Unimodular Lattices and Invariant Rings, IEEE Trans. Information Theory, Volume 45, Number 4, 1999, 1194-1205.
Index entries for linear recurrences with constant coefficients, signature (1, 1, 0, -1, -1, 2, -1, -1, 0, 1, 1, -1).
FORMULA
G.f.: (x^9+x^8-x^7+5*x^6-x^5+x^4+2*x^3-x+1)/((x-1)^4*(x+1)^2*(x^2+x+1)^2*(x^2-x+1)).
a(0)=1, a(1)=0, a(2)=1, a(3)=3, a(4)=4, a(5)=5, a(6)=15, a(7)=14, a(8)=24, a(9)=35, a(10)=44, a(11)=54, a(n)=a(n-1)+a(n-2)-a(n-4)-a(n-5)+ 2*a(n-6)-a(n-7)-a(n-8)+a(n-10)+a(n-11)-a(n-12). - Harvey P. Dale, Jun 15 2013
a(n) ~ 1/27 * n^3. - Ralf Stephan, May 17 2014
MATHEMATICA
CoefficientList[Series[(x^9+x^8-x^7+5x^6-x^5+x^4+2x^3-x+1)/((x-1)^4 (x+1)^2(x^2+x+1)^2(x^2-x+1)), {x, 0, 50}], x] (* or *) LinearRecurrence[ {1, 1, 0, -1, -1, 2, -1, -1, 0, 1, 1, -1}, {1, 0, 1, 3, 4, 5, 15, 14, 24, 35, 44, 54}, 50] (* Harvey P. Dale, Jun 15 2013 *)
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
EXTENSIONS
More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jun 15 2001
STATUS
approved