A011932 [ n(n-1)(n-2)(n-3)/22 ].

0, 0, 0, 0, 1, 5, 16, 38, 76, 137, 229, 360, 540, 780, 1092, 1489, 1985, 2596, 3338, 4228, 5285, 6529, 7980, 9660, 11592, 13800, 16309, 19145, 22336, 25910, 29896, 34325, 39229, 44640, 50592, 57120, 64260

Offset

0,6

Links

Table of n, a(n) for n=0..36.

Index entries for linear recurrences with constant coefficients, signature (4, -6, 4, -1, 0, 0, 0, 0, 0, 0, 1, -4, 6, -4, 1).

Formula

From Chai Wah Wu, Aug 02 2020: (Start)

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + a(n-11) - 4*a(n-12) + 6*a(n-13) - 4*a(n-14) + a(n-15) for n > 14.

G.f.: -x^4*(x^10 + x^9 + 2*x^8 + x^6 + 2*x^5 + x^4 + 2*x^2 + x + 1)/((x - 1)^5*(x^10 + x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x + 1)). (End)

Mathematica

Table[Floor[(n(n-1)(n-2)(n-3))/22], {n, 0, 40}] (* Harvey P. Dale, Nov 25 2017 *)

Prog

(PARI) a(n)=n*(n-1)*(n-2)*(n-3)\22 \\ Charles R Greathouse IV, Oct 18 2022

Crossrefs

Sequence in context: A218259 A211807 A174723 * A357289 A131283 A082199

Adjacent sequences: A011929 A011930 A011931 * A011933 A011934 A011935

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved