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A104600
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Number of matrices of any size up to column permutations, with n different elements, zero elsewhere and with no zero row or column.
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2
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1, 1, 5, 49, 795, 18881, 611193, 25704253, 1356235163, 87419692453, 6741175388313, 611464105166993, 64336296019640307, 7760748741918246361, 1062626712168331953737, 163738827988386433177093
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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LINKS
| M. Maia and M. Mendez, On the arithmetic product of combinatorial species
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FORMULA
| (1/(2e)) * Sum{r, s>=0, (rs)_n / [2^r s! ] }, where (m)_n is the falling factorial m * (m-1) * ... * (m-n+1).
E.g.f.: exp(-1)*sum(exp((1+x)^n)/2^(n+1),n=0..infinity). - Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 24 2006
a(n) = Sum_{k=0..n} Stirling1(n,k)*A000670(k)*A000110(k). - Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 27 2006
exp(-1)*sum(1/(2-(1+x)^n)/n!,n=0..infinity) is also e.g.f. - Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 09 2006
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CROSSREFS
| Sequence in context: A145088 A192557 A062995 * A002111 A001819 A064618
Adjacent sequences: A104597 A104598 A104599 * A104601 A104602 A104603
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KEYWORD
| nonn
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AUTHOR
| Ralf Stephan, Mar 27 2005
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EXTENSIONS
| Corrected by Vladeta Jovovic, Sep 08 2006
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