OFFSET
0,5
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..2000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1,0,0,0,0,0,0,0,1,-3,3,-1).
FORMULA
a(n) = +3*a(n-1) -3*a(n-2) +a(n-3) +a(n-11) -3*a(n-12) +3*a(n-13) -a(n-14). - R. J. Mathar, Apr 15 2010
G.f.: x^4*(2-x+x^2+2*x^3-2*x^4+2*x^5+x^6+x^9)/((1-x)^4*(1+x+x^2+x^3+x^4+x^5 +x^6+x^7+x^8+x^9+x^10)). - Peter J. C. Moses, Jun 02 2014
MATHEMATICA
Table[Floor[n(n-1)(n-2)/11], {n, 0, 40}] (* or *)
LinearRecurrence[{3, -3, 1, 0, 0, 0, 0, 0, 0, 0, 1, -3, 3, -1}, {0, 0, 0, 0, 2, 5, 10, 19, 30, 45, 65, 90, 120, 156}, 50] (* Harvey P. Dale, Nov 23 2018 *)
PROG
(Magma) [Floor(6*Binomial(n, 3)/11): n in [0..50]]; // G. C. Greubel, Oct 06 2024
(SageMath) [6*binomial(n, 3)//11 for n in range(51)] # G. C. Greubel, Oct 06 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
a(41) onwards from G. C. Greubel, Oct 06 2024
STATUS
approved