A004204 Number of permutations of length n with spread 0.
1, 1, 0, 4, 20, 144, 630, 5696, 39366, 366400, 3634950, 39066624, 479163828, 6226534272, 87238701000, 1315130458112, 20922813624336, 355586138666496, 6402373841107998, 121479626301440000
Offset: 1
Keywords
References
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Links
- Rintaro Matsuo, Table of n, a(n) for n = 1..40
- 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.
- Rintaro Matsuo, Code used to calculate up to a(40)
Crossrefs
Column k=0 of A147679.
Programs
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PARI
a(n) = my(v=[1..n], nb=0); forperm(v, p, if (sum(i=1, n-1, Mod(i,n)*p[i]) == 0, nb++)); nb; \\ Michel Marcus, Nov 30 2022
Extensions
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 17 2007
Comments