A011933 a(n) = floor( n*(n-1)*(n-2)*(n-3)/23 ).

0, 0, 0, 0, 1, 5, 15, 36, 73, 131, 219, 344, 516, 746, 1044, 1424, 1899, 2483, 3193, 4044, 5055, 6245, 7633, 9240, 11088, 13200, 15600, 18313, 21365, 24783, 28596, 32833, 37523, 42699, 48392, 54636, 61466

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, 0, 0, 0, 0, 0, 0, 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-23) - 4*a(n-24) + 6*a(n-25) - 4*a(n-26) + a(n-27) for n > 26.

G.f.: x^4*(-x^22 - x^21 - x^20 - 2*x^19 - 4*x^16 + 2*x^15 - 3*x^14 - x^13 + x^12 - 4*x^11 + x^10 - x^9 - 3*x^8 + 2*x^7 - 4*x^6 - 2*x^3 - x^2 - x - 1)/(x^27 - 4*x^26 + 6*x^25 - 4*x^24 + x^23 - x^4 + 4*x^3 - 6*x^2 + 4*x - 1). (End)

Mathematica

Table[Floor[(n(n-1)(n-2)(n-3))/23], {n, 0, 40}] (* Harvey P. Dale, Jun 22 2011 *)

Prog

(PARI) a(n) = n*(n-1)*(n-2)*(n-3)\23; \\ Michel Marcus, Jun 14 2017

Crossrefs

Cf. A000332, A052762.

Sequence in context: A174655 A184631 A366971 * A093802 A006008 A325952

Adjacent sequences: A011930 A011931 A011932 * A011934 A011935 A011936

Keyword

easy,nonn

Author

N. J. A. Sloane

Status

approved