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Search: id:A107873
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| A107873 |
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Triangle, read by rows, where T(n,k) = C(n*(n-1)/2-k*(k-1)/2+n-k+3, n-k). |
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+0
11
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| 1, 4, 1, 15, 5, 1, 84, 28, 6, 1, 715, 220, 45, 7, 1, 8568, 2380, 455, 66, 8, 1, 134596, 33649, 5985, 816, 91, 9, 1, 2629575, 593775, 98280, 12650, 1330, 120, 10, 1, 61523748, 12620256, 1947792, 237336, 23751, 2024, 153, 11, 1, 1677106640
(list; table; graph; listen)
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OFFSET
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0,2
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COMMENT
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Remarkably, the following matrix products are all equal to A107876: A107862^-1*A107867 = A107867^-1*A107870 = A107870^-1*A107873.
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EXAMPLE
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Triangle begins:
1;
4,1;
15,5,1;
84,28,6,1;
715,220,45,7,1;
8568,2380,455,66,8,1;
134596,33649,5985,816,91,9,1;
2629575,593775,98280,12650,1330,120,10,1; ...
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PROGRAM
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(PARI) T(n, k)=binomial(n*(n-1)/2-k*(k-1)/2 +n-k+3, n-k)
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CROSSREFS
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Cf. A107862, A107865, A107867, A107876, A107870, A107874, A107875.
Adjacent sequences: A107870 A107871 A107872 this_sequence A107874 A107875 A107876
Sequence in context: A050156 A096644 A016115 this_sequence A080419 A095307 A124029
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KEYWORD
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nonn,tabl
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jun 04 2005
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