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Search: id:A066300
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| A066300 |
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Number of n X n matrices with exactly 2 1's in each row, other entries 0. |
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+0
2
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| 0, 1, 27, 1296, 100000, 11390625, 1801088541, 377801998336, 101559956668416, 34050628916015625, 13931233916552734375, 6831675453247426400256, 3955759092264800909058048, 2670419511272061205254504361
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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a(n) = C(n, 2)^n
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MAPLE
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seq(mul(sum(j, j=1..n), k=0..n), n=0..13); # and seq(mul(stirling2(n, n-1), k=1..n), n=1..14); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 02 2007
a:=n->mul(sum(j, j=0..n), k=0..n): seq(a(n), n=0..13); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 02 2007
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MATHEMATICA
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Table[ Binomial[n, 2]^n, {n, 1, 16} ]
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CROSSREFS
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Cf. A001499.
Adjacent sequences: A066297 A066298 A066299 this_sequence A066301 A066302 A066303
Sequence in context: A132059 A017019 A104206 this_sequence A075547 A017103 A042407
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KEYWORD
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nonn
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AUTHOR
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Sharon Sela (sharonsela(AT)hotmail.com), Jan 01 2002
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 03 2002
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