A121987 a(n + 4) = (n + 2)*(a(n + 3) - a(n) + 1) for n > 3, a(0) = a(1) = a(2) = a(3) = 1.

1, 1, 1, 1, 2, 6, 24, 120, 714, 4963, 39520, 354609, 3538960, 38873978, 466013508, 6053565700, 84700374374, 1269922505955, 20311303879168, 345189255328973, 6211881989182800, 118001629266860074, 2359626359259618140

Offset

0,5

Links

G. C. Greubel, Table of n, a(n) for n = 0..450

Mathematica

RecurrenceTable[{a[n + 4] == (n + 2)*(a[n + 3] - a[n] + 1), a[0] == 1, a[1] == 1, a[2] == 1, a[3] == 1}, a, {n, 0, 50}] (* G. C. Greubel, Sep 14 2017 *)

Crossrefs

Sequence in context: A324134 A324135 A177531 * A324132 A177524 A223905

Adjacent sequences: A121984 A121985 A121986 * A121988 A121989 A121990

Keyword

nonn,easy

Author

Roger L. Bagula, Sep 10 2006

Extensions

Edited by N. J. A. Sloane, Jun 17 2007

Edited and name changed by G. C. Greubel, Sep 14 2017

Status

approved