OFFSET
0,5
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1,0,0,0,1,-3,3,-1).
FORMULA
From R. J. Mathar, Apr 15 2010: (Start)
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-7) - 3*a(n-8) + 3*a(n-9) - a(n-10).
G.f.: x^4*(3-x+2*x^2+x^4+x^5) / ( (1-x)^4*(1+x+x^2+x^3+x^4+x^5+x^6) ). (End)
MATHEMATICA
CoefficientList[Series[x^4*(3-x+2*x^2+x^4+x^5)/((-1+x)^4*(1+x+x^2+x^3+ x^4+x^5+x^6)), {x, 0, 50}], x] (* Vincenzo Librandi Jul 07 2012 *)
Floor[6*Binomial[Range[0, 50], 3]/7] (* G. C. Greubel, Oct 06 2024 *)
PROG
(Magma) [Floor(n*(n-1)*(n-2)/7): n in [0..50]]; // Vincenzo Librandi, Jul 07 2012
(SageMath) [6*binomial(n, 3)//7 for n in range(51)] # G. C. Greubel, Oct 06 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved