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Search: id:A107870
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| A107870 |
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Triangle, read by rows, where T(n,k) = C(n*(n-1)/2-k*(k-1)/2+n-k+2, n-k). |
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+0
12
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| 1, 3, 1, 10, 4, 1, 56, 21, 5, 1, 495, 165, 36, 6, 1, 6188, 1820, 364, 55, 7, 1, 100947, 26334, 4845, 680, 78, 8, 1, 2035800, 475020, 80730, 10626, 1140, 105, 9, 1, 48903492, 10295472, 1623160, 201376, 20475, 1771, 136, 10, 1, 1362649145, 260932815
(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;
3,1;
10,4,1;
56,21,5,1;
495,165,36,6,1;
6188,1820,364,55,7,1;
100947,26334,4845,680,78,8,1;
2035800,475020,80730,10626,1140,105,9,1; ...
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PROGRAM
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(PARI) T(n, k)=binomial(n*(n-1)/2-k*(k-1)/2 +n-k+2, n-k)
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CROSSREFS
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Cf. A107862, A107865, A107867, A107876, A107871, A107872.
Sequence in context: A134285 A141811 A126954 this_sequence A078817 A091042 A111418
Adjacent sequences: A107867 A107868 A107869 this_sequence A107871 A107872 A107873
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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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