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,-3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-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-25) -3*a(n-26) +3*a(n-27) -a(n-28).
G.f.: x^5*(2-2*x+2*x^2-x^3+x^4-x^5+2*x^6-x^7+x^8+x^12-x^13+2*x^14-x^15+x^16-x^17+2*x^18-2*x^19+3*x^20-2*x^21+x^22) / ( (1-x)^4*(1+x^4+x^3+x^2+x)*(1+x^5+x^10+x^15+x^20) ). (End)
MATHEMATICA
Table[Floor[(n(n-1)(n-2))/25], {n, 0, 75}] (* Harvey P. Dale, Aug 25 2021 *)
PROG
(PARI) a(n)=n*(n-1)*(n-2)\25 \\ Charles R Greathouse IV, Oct 21 2022
(Magma) [Floor(6*Binomial(n, 3)/25): n in [0..75]]; // G. C. Greubel, Oct 18 2024
(SageMath) [6*binomial(n, 3)//25 for n in range(76)] # G. C. Greubel, Oct 18 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms added by G. C. Greubel, Oct 18 2024
STATUS
approved