A185781 Accumulation array of A185780, by antidiagonals.
1, 5, 2, 14, 12, 3, 30, 36, 21, 4, 55, 80, 66, 32, 5, 91, 150, 150, 104, 45, 6, 140, 252, 285, 240, 150, 60, 7, 204, 392, 483, 460, 350, 204, 77, 8, 285, 576, 756, 784, 675, 480, 266, 96, 9, 385, 810, 1116, 1232, 1155, 930, 630, 336, 117, 10, 506, 1100, 1575, 1824, 1820, 1596, 1225, 800, 414, 140, 11, 650, 1452, 2145, 2580, 2700, 2520, 2107, 1560, 990, 500, 165, 12
Offset: 1
Examples
Northwest corner: 1.....5....14....30....55 2.....12...36....80....150 3.....21...66....150...285 4.....32...104...240...460 5.....45...150...350...675
Links
- G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened
Programs
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Mathematica
(See A185780.) f[n_, k_] := k*(k + 1)*n*(k*n - n + k + 2)/6; Table[f[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten (* G. C. Greubel, Jul 12 2017 *)
Formula
T(n,k) = k*(k+1)*n*(k*n-n+k+2)/6, k>=1, n>=1.
Comments