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Search: id:A094223
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| A094223 |
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Number of binary n X n matrices with all rows (columns) distinct, up to permutation of columns (rows). |
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+0
1
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| 1, 2, 7, 68, 2251, 247016, 89254228, 108168781424, 451141297789858, 6625037125817801312, 348562672319990399962384, 66545827618461283102105245248, 46543235997095840080425299916917968
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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G. Kilibarda and V. Jovovic, "Enumeration of some classes of T_0-hypergraphs", in preparation, 2004.
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FORMULA
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a(n) = Sum((-1)^(n-k)*Stirling1(n, k)*binomial(2^k, n), k=0..n) = Sum(Stirling1(n, k)*binomial(2^k+n-1, n), k=0..n).
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MATHEMATICA
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a[n_] := Sum[(-1)^(n - k)*StirlingS1[n, k]*Binomial[2^k, n], {k, 0, n}]; (* or *) a[n_] := Sum[ StirlingS1[n, k]*Binomial[2^k + n - 1, n], {k, 0, n}]; Table[ a[n], {n, 0, 12}] (from Robert G. Wilson v May 29 2004)
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CROSSREFS
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Main diagonal of A059584 and A059587, A060690, A088309.
Sequence in context: A042051 A133237 A099660 this_sequence A113866 A106917 A061421
Adjacent sequences: A094220 A094221 A094222 this_sequence A094224 A094225 A094226
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KEYWORD
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easy,nonn
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AUTHOR
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Goran Kilibarda, Vladeta Jovovic (vladeta(AT)Eunet.yu), May 28 2004
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), May 29 2004
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