A060836 Number of permutations of n letters where exactly 5 change position.

0, 0, 0, 0, 44, 264, 924, 2464, 5544, 11088, 20328, 34848, 56628, 88088, 132132, 192192, 272272, 376992, 511632, 682176, 895356, 1158696, 1480556, 1870176, 2337720, 2894320, 3552120, 4324320, 5225220, 6270264, 7476084, 8860544

Offset

1,5

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Formula

a(n) = 44*C(n, 5). a(n) = a(n-1)*n/(n-5).

G.f.: 44*x^5/(1-x)^6. [Colin Barker, Apr 22 2012]

Example

a(8) = a(7) x 8/(8-5) = 924 x 8/3 = 2464

Prog

(PARI) { for (n=1, 1000, if (n>5, a*=n/(n - 5), if (n<5, a=0, a=44)); write("b060836.txt", n, " ", a); ) } \\ Harry J. Smith, Jul 19 2009

Crossrefs

For changing 0, 1, 2, 3, 4, 5, n-4, n elements see A000012, A000004, A000217 (offset), A007290, A060008, A060836, A000475, A000166. Also see A000332, A008290.

Rencontre sequences are A000166 A000240 A000387 A000449 and A000475.

A diagonal of A008291.

Sequence in context: A031175 A098826 A160284 * A135182 A094794 A001689

Adjacent sequences: A060833 A060834 A060835 * A060837 A060838 A060839

Keyword

nonn,easy

Author

Robert Goodhand (rgoodhand(AT)hotmail.com), May 12 2001

Status

approved