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A123490
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Triangle whose k-th column satisfies a(n) = (k+3)*a(n-1)-(k+2)*a(n-2).
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3
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1, 2, 1, 4, 2, 1, 8, 5, 2, 1, 16, 14, 6, 2, 1, 32, 41, 22, 7, 2, 1, 64, 122, 86, 32, 8, 2, 1, 128, 365, 342, 157, 44, 9, 2, 1, 256, 1094, 1366, 782, 260, 58, 10, 2, 1, 512, 3281, 5462, 3907, 1556, 401, 74, 11, 2, 1, 1024, 9842, 21846, 19532, 9332, 2802, 586, 92, 12, 2, 1
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OFFSET
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0,2
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LINKS
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FORMULA
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Column k has g.f.: x^k*(1-x(1+k))/((1-x)*(1-x(2+k))).
T(n,k) = ((k+2)^(n-k) + k)/(k+1), for 0 <= k <= n.
Sum_{k=0..n} T(n, k) = A103439(n+1).
Sum_{k=0..floor(n/2)} T(n-k, k) = A123491(n).
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EXAMPLE
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Triangle begins
1;
2, 1;
4, 2, 1;
8, 5, 2, 1;
16, 14, 6, 2, 1;
32, 41, 22, 7, 2, 1;
64, 122, 86, 32, 8, 2, 1;
128, 365, 342, 157, 44, 9, 2, 1;
256, 1094, 1366, 782, 260, 58, 10, 2, 1;
512, 3281, 5462, 3907, 1556, 401, 74, 11, 2, 1;
1024, 9842, 21846, 19532, 9332, 2802, 586, 92, 12, 2, 1;
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MATHEMATICA
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Table[((k+2)^(n-k) +k)/(k+1), {n, 0, 12}, {k, 0, n}]//Flatten (* G. C. Greubel, Oct 14 2017 *)
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PROG
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(PARI) for(n=0, 10, for(k=0, n, print1(((k+2)^(n-k)+k)/(k+1), ", "))) \\ G. C. Greubel, Oct 14 2017
(Magma) [((k+2)^(n-k) +k)/(k+1): k in [0..n], n in [0..12]]; // G. C. Greubel, Jun 15 2021
(Sage) flatten([[((k+2)^(n-k) +k)/(k+1) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jun 15 2021
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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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