A111112 a(n) = 412*n^6 - 408*n^5 - 1130*n^4 - 360*n^3 + 2368*n^2 - 912*n + 15*(1 - (-1)^n).

0, 0, 0, 118560, 991680, 4465920, 14587200, 38887200, 89965440, 187368960, 359767680, 647427360, 1104978240, 1804481280, 2838790080, 4325210400, 6409455360, 9269898240, 13122120960, 18223760160, 24879648960, 33447256320, 44342422080, 58045389600, 75107134080, 96155988480, 121904565120

Offset

0,4

Links

Table of n, a(n) for n=0..26.

Vania Mascioni, On the probability that finite spaces with random points are metric spaces, Discr. Math., Vol. 300, Iss. 1-3 (2005), pp. 129-138.

Index entries for linear recurrences with constant coefficients, signature (6,-14,14,0,-14,14,-6,1).

Formula

From Elmo R. Oliveira, May 11 2026: (Start)

G.f.: 480*x^3*(247 + 584*x + 366*x^2 + 32*x^3 + 7*x^4)/((1 + x)*(1 - x)^7).

a(n) = 6*a(n-1) - 14*a(n-2) + 14*a(n-3) - 14*a(n-5) + 14*a(n-6) - 6*a(n-7) + a(n-8).

E.g.f.: exp(x)*(15 - 30*x + 30*x^2 + 19740*x^3 + 21570*x^4 + 5772*x^5 + 412*x^6) - 15*exp(-x). (End)

Mathematica

Table[412n^6-408n^5-1130n^4-360n^3+2368n^2-912n+15(1-(-1)^n), {n, 0, 30}] (* Harvey P. Dale, Jul 08 2020 *)

Crossrefs

Sequence in context: A394984 A235837 A235832 * A145306 A250370 A202285

Adjacent sequences: A111109 A111110 A111111 * A111113 A111114 A111115

Keyword

nonn,easy

Author

N. J. A. Sloane, Oct 14 2005

Extensions

More terms from Georg Fischer, Feb 23 2021

Status

approved