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A055602
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Number of n X n binary matrices with no zero rows or columns and with n+1 ones.
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7
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0, 4, 45, 432, 4200, 43200, 476280, 5644800, 71850240, 979776000, 14270256000, 221298739200, 3642807168000, 63465795993600, 1167099373440000, 22596613079040000, 459548157100032000, 9795631769763840000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| Number of m X n binary matrices with no zero rows or columns and with k=0..m*n ones is Sum_{i=0..n} (-1)^i*binomial(n, i)*a(m, n-i, k) where a(m, n, k)=Sum_{i=0..m} (-1)^i*binomial(m, i)*binomial((m-i)*n, k).
a(n) = n*(n-1)*(n+2)*n!/4. - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 25 2006
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CROSSREFS
| A diagonal of triangle A104601.
Cf. A055603.
Sequence in context: A123650 A122910 A117644 * A073565 A039657 A114473
Adjacent sequences: A055599 A055600 A055601 * A055603 A055604 A055605
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KEYWORD
| nonn
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 01 2000
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EXTENSIONS
| More terms from David Wasserman (dwasserm(AT)earthlink.net), Apr 28 2002
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