OFFSET
0,6
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..2000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-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-20) -3*a(n-21) +3*a(n-22) -a(n-23).
G.f.: x^4*(1+x^4+x^5-x^6+2*x^8-2*x^9+3*x^10-2*x^11+2*x^12-x^13+2*x^15-x^17+x^18)/((1-x)^4*(1+x)*(1+x^2)*(1+x+x^2+x^3+x^4)*(1-x+x^2-x^3+x^4)*(1-x^2+x^4-x^6+x^8)). (End)
MATHEMATICA
Table[Floor[(n(n-1)(n-2))/20], {n, 0, 80}] (* Harvey P. Dale, Mar 23 2011 *)
PROG
(Magma) [Floor(3*Binomial(n, 3)/10): n in [0..80]]; // G. C. Greubel, Oct 18 2024
(SageMath) [3*binomial(n, 3)//10 for n in range(81)] # G. C. Greubel, Oct 18 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms added by G. C. Greubel, Oct 18 2024
STATUS
approved