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Search: id:A122400
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| A122400 |
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Number of square (0,1)-matrices without zero rows and with exactly n entries equal to 1. |
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+0
3
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| 1, 1, 4, 31, 338, 4769, 82467, 1687989, 39905269, 1069863695, 32071995198, 1062991989013, 38596477083550, 1523554760656205, 64961391010251904, 2975343608212835855, 145687881987604377815, 7594435556630244257213
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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a(n) = (1/n!)* Sum_{k=0..n} Stirling1(n,k)*A122399(k).
G.f.: Sum(((1+x)^n-1)^n,n=0..infinity). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Sep 03 2006
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MAPLE
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A122399 := proc(n) option remember ; add( combinat[stirling2](n, k)*k^n*k!, k=0..n) ; end: A122400 := proc(n) option remember ; add( combinat[stirling1](n, k)*A122399(k), k=0..n)/n! ; end: for n from 0 to 30 do printf("%d, ", A122400(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 18 2007
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CROSSREFS
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Cf. A104602.
Sequence in context: A003436 A114475 A076280 this_sequence A107725 A129271 A136728
Adjacent sequences: A122397 A122398 A122399 this_sequence A122401 A122402 A122403
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 31 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 18 2007
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