A011911 a(n) = floor( n*(n-1)*(n-2)/29 ).

0, 0, 0, 0, 0, 2, 4, 7, 11, 17, 24, 34, 45, 59, 75, 94, 115, 140, 168, 200, 235, 275, 318, 366, 418, 475, 537, 605, 677, 756, 840, 930, 1026, 1128, 1238, 1354, 1477, 1607, 1745, 1890, 2044, 2205, 2375, 2553, 2740, 2935, 3140, 3354, 3578, 3811, 4055, 4308, 4572, 4846, 5131, 5427, 5735, 6053, 6384, 6726, 7080, 7446, 7824, 8216, 8620, 9037, 9467, 9911, 10368, 10840

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..2000
• Index entries for linear recurrences with constant coefficients, signature (3,-3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-3,3,-1).

Crossrefs

Cf. A011886.

Programs

Magma

[Floor(6*Binomial(n,3)/29): n in [0..80]]; // G. C. Greubel, Oct 19 2024

Mathematica

Floor[6*Binomial[Range[0,75], 3]/29] (* G. C. Greubel, Oct 19 2024 *)
Table[Floor[(2n-3n^2+n^3)/29],{n,0,100}] (* Harvey P. Dale, Jan 25 2025 *)

SageMath

[6*binomial(n,3)//29 for n in range(81)] # G. C. Greubel, Oct 19 2024

Formula

G.f.: x^5*(2+x*(-2+x+x^3-x^4+2*x^5-2*x^6+2*x^7-x^8+x^9-x^10+2*x^11-x^12+x^13-x^14+2*x^15-2*x^16+2*x^17-x^18+x^19+x^21-2*x^22+3*x^23-2*x^24+x^25))/((1-x)^3*(1-x^29)). - Peter J. C. Moses, Jun 02 2014

Extensions

More terms added by G. C. Greubel, Oct 19 2024