A208657 Triangular array read by rows: n*binomial(n,n-k+1)-binomial(n-1,n-k) with k = 1..n, n >= 1.
0, 1, 3, 2, 7, 8, 3, 13, 21, 15, 4, 21, 44, 46, 24, 5, 31, 80, 110, 85, 35, 6, 43, 132, 225, 230, 141, 48, 7, 57, 203, 413, 525, 427, 217, 63, 8, 73, 296, 700, 1064, 1078, 728, 316, 80, 9, 91, 414, 1116, 1974, 2394, 2016, 1164, 441, 99, 10, 111, 560, 1695
Offset: 1
Examples
Triangle begins: 0, 1, 3, 2, 7, 8, 3, 13, 21, 15, 4, 21, 44, 46, 24, 5, 31, 80, 110, 85, 35, 6, 43, 132, 225, 230, 141, 48, 7, 57, 203, 413, 525, 427, 217, 63, 8, 73, 296, 700, 1064, 1078, 728, 316, 80, 9, 91, 414, 1116, 1974, 2394, 2016, 1164, 441, 99; ...
Programs
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Magma
[n*Binomial(n,n-k+1)-Binomial(n-1,n-k): k in [1..n], n in [1..11]]; // Bruno Berselli, Apr 15 2015
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Mathematica
z = 12; f[n_, k_] := n*Binomial[n, k] - Binomial[n - 1, k - 1] t = Table[f[n, k], {n, 1, z}, {k, 1, n}]; TableForm[t] (* A208656 as a triangle *) Flatten[t] (* A208656 as a sequence *) r = Table[f[n, k], {n, 1, z}, {k, n, 1, -1}]; TableForm[r] (* A208657 as a triangle *) Flatten[r] (* A208657 as a sequence *) Table[Sum[f[n, k], {k, 1, n}], {n, 1, 3 z}](* A208658 *)
Comments