A011941 a(n) = floor(n*(n-1)*(n-2)*(n-3)/31).

0, 0, 0, 0, 0, 3, 11, 27, 54, 97, 162, 255, 383, 553, 774, 1056, 1409, 1842, 2369, 3000, 3750, 4633, 5663, 6855, 8226, 9793, 11574, 13587, 15851, 18387, 21216, 24360, 27840, 31680, 35904, 40536, 45603, 51131, 57147, 63678, 70753, 78402, 86655, 95543

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Robert Israel, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-4,6,-4,1).

Crossrefs

Cf. A011915.

Programs

Magma

[Floor(24*Binomial(n,4)/31): n in [0..60]]; // G. C. Greubel, Oct 26 2024

Maple

f:= n -> floor(n*(n-1)*(n-2)*(n-3)/31):
map(f, [$0..100]); # Robert Israel, Feb 12 2017

Mathematica

Floor[24*Binomial[Range[0, 60], 4]/31] (* G. C. Greubel, Oct 26 2024 *)

PARI

a(n) = n*(n-1)*(n-2)*(n-3)\31; \\ Altug Alkan, Feb 12 2017

SageMath

[24*binomial(n,4)//31 for n in range(61)] # G. C. Greubel, Oct 26 2024

Formula

G.f.: (3-x+x^2+2*x^4+x^5+x^7+2*x^9+x^10-x^12+5*x^13-4*x^14+5*x^15-x^16+x^18 +2*x^19+x^21+x^23+2*x^24+x^26-x^27+3*x^28)*x^5/((1-x)^4*(1-x^31)). - Robert Israel, Feb 12 2017