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A107862
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Triangle, read by rows, where T(n,k) = C(n*(n-1)/2 - k*(k-1)/2 + n-k, n-k).
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13
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1, 1, 1, 3, 2, 1, 20, 10, 3, 1, 210, 84, 21, 4, 1, 3003, 1001, 220, 36, 5, 1, 54264, 15504, 3060, 455, 55, 6, 1, 1184040, 296010, 53130, 7315, 816, 78, 7, 1, 30260340, 6724520, 1107568, 142506, 14950, 1330, 105, 8, 1, 886163135, 177232627, 26978328, 3262623, 324632, 27405, 2024, 136, 9, 1
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OFFSET
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0,4
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COMMENTS
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LINKS
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FORMULA
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T(n,k) = binomial( (n-k)*(n+k+1)/2, n-k). - G. C. Greubel, Feb 19 2022
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EXAMPLE
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Triangle begins:
1;
1, 1;
3, 2, 1;
20, 10, 3, 1;
210, 84, 21, 4, 1;
3003, 1001, 220, 36, 5, 1;
54264, 15504, 3060, 455, 55, 6, 1;
1184040, 296010, 53130, 7315, 816, 78, 7, 1; ...
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MATHEMATICA
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T[n_, k_]:= Binomial[(n-k)*(n+k+1)/2, n-k];
Table[T[n, k], {n, 0, 12}, {k, 0, n}]//Flatten (* G. C. Greubel, Feb 19 2022 *)
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PROG
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(PARI) T(n, k)=binomial(n*(n-1)/2-k*(k-1)/2+n-k, n-k)
(Magma) [Binomial(Floor((n-k)*(n+k+1)/2), n-k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 19 2022
(Sage) flatten([[binomial( (n-k)*(n+k+1)/2, n-k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 19 2022
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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