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A104602
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Number of square (0,1)-matrices with exactly n entries equal to 1 and no zero row or columns.
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7
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1, 2, 10, 70, 642, 7246, 97052, 1503700, 26448872, 520556146, 11333475922, 270422904986, 7016943483450, 196717253145470, 5925211960335162, 190825629733950454, 6543503207678564364, 238019066600097607402
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Number of square (0,1)-matrices with exactly n entries equal to 1 and no zero row or columns, up to row and column permutation, is A057151(n). - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 25 2006
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LINKS
| M. Maia and M. Mendez, On the arithmetic product of combinatorial species
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FORMULA
| a(n) = (1/n!)*Sum_{k=0..n} Stirling1(n,k)*A048144(k). - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 25 2006
G.f.: Sum_{n>=0} Sum_{j=0..n} (-1)^(n-j)*binomial(n,j)*((1+x)^j-1)^n. - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 25 2006
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CROSSREFS
| Row sums of triangle A104601.
Sequence in context: A036075 A123881 A089845 * A118748 A118752 A060842
Adjacent sequences: A104599 A104600 A104601 * A104603 A104604 A104605
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KEYWORD
| nonn
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AUTHOR
| Ralf Stephan, Mar 27 2005
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EXTENSIONS
| More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 25 2006
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