OFFSET
0,4
REFERENCES
Blyth and Robonson, Essential Student Algebra, V5, Groups, J. W. Arrowsmith, Bristol, 1986, page 9.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
FORMULA
From R. J. Mathar, Nov 28 2008: (Start)
a(n) = 6*a(n-6) + a(n-12).
G.f.: x*(1+x+2*x^2+2*x^3+5*x^4+5*x^5-3*x^6+2*x^7-x^8-x^9)/(1-6*x^6-x^12).
a(6n+1) = A005667(n). (End)
MATHEMATICA
CoefficientList[Series[x*(1 + x + 2*x^2 + 2*x^3 + 5*x^4 + 5*x^5 - 3*x^6 + 2*x^7 - x^8 - x^9)/(1 - 6*x^6 - x^12), {x, 0, 50}], x] (* G. C. Greubel, Sep 20 2017 *)
PROG
(PARI) x='x+O('x^50); Vec(x*(1 + x + 2*x^2 + 2*x^3 + 5*x^4 + 5*x^5 - 3*x^6 + 2*x^7 - x^8 - x^9)/(1 - 6*x^6 - x^12)) \\ G. C. Greubel, Sep 20 2017
CROSSREFS
KEYWORD
nonn,obsc
AUTHOR
Roger L. Bagula, Mar 17 2006
EXTENSIONS
More terms added by G. C. Greubel, Sep 20 2017
STATUS
approved