A004206 - OEIS

A004206

Number of permutations of length n with spread 2.
(Formerly M2381)

3, 4, 25, 108, 735, 5248, 40824, 362000, 3628185, 39045888, 478988081, 6227101888, 87146087625, 1314459353088, 20922788404479, 355737629952000, 6402373698206889, 121479069952000000

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OFFSET

3,1

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=3..20.

R. L. Graham and D. H. Lehmer, On the Permanent of Schur's Matrix, Jour. Australian Math. Soc. 21 no. 4 (series A) (1976), 487-497.

CROSSREFS

Sequence in context: A192346 A335739 A055348 * A302397 A151372 A258103

Adjacent sequences: A004203 A004204 A004205 * A004207 A004208 A004209

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 17 2007

STATUS

approved