A005778 Rook polynomials. (Formerly M4647)

1, 9, 72, 320, 1185, 3892, 11776, 33480, 90745, 236808, 599112, 1477216, 3564001, 8439960, 19666688, 45183824, 102520881, 230046452, 511085960, 1125313056, 2457641857, 5327760940, 11471647872, 24547187800, 52225646057, 110524638672

Offset

1,2

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..26.

Earl Glen Whitehead, Jr., Four-discordant permutations, J. Austral. Math. Soc. Ser. A 28 (1979), no. 3, 369-377.

Crossrefs

A diagonal of A259985.

Sequence in context: A069978 A070823 A073988 * A288351 A319892 A319873

Adjacent sequences: A005775 A005776 A005777 * A005779 A005780 A005781

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms from Sean A. Irvine, Aug 27 2016

Status

approved