OFFSET
0,2
REFERENCES
P. de la Harpe, Topics in Geometric Group Theory, Univ. Chicago Press, 2000, p. 160, Sigma(Gamma_3, S_3; z).
LINKS
Colin Barker, Table of n, a(n) for n = 0..900
Index entries for linear recurrences with constant coefficients, signature (10,10,10,10,10,-1).
FORMULA
G.f.: (1+x)*(1-x^6) / (1 - 11*x + 11*x^6 - x^7).
From Colin Barker, Jun 11 2019: (Start)
G.f.: (1 + x)^2*(1 - x + x^2)*(1 + x + x^2) / (1 - 10*x - 10*x^2 - 10*x^3 - 10*x^4 - 10*x^5 + x^6).
a(n) = 10*a(n-1) + 10*a(n-2) + 10*a(n-3) + 10*a(n-4) + 10*a(n-5) - a(n-6) for n>6.
(End)
MATHEMATICA
LinearRecurrence[{10, 10, 10, 10, 10, -1}, {1, 12, 132, 1452, 15972, 175692, 1932600}, 20] (* Harvey P. Dale, Jul 19 2019 *)
PROG
(PARI) Vec((1 + x)^2*(1 - x + x^2)*(1 + x + x^2) / (1 - 10*x - 10*x^2 - 10*x^3 - 10*x^4 - 10*x^5 + x^6) + O(x^20)) \\ Colin Barker, Jun 11 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Aug 21 2001
STATUS
approved