A185733 Second accumulation array of the polygonal number array (A086270), by antidiagonals.
1, 5, 3, 15, 16, 6, 35, 50, 34, 10, 70, 120, 110, 60, 15, 126, 245, 270, 200, 95, 21, 210, 448, 560, 500, 325, 140, 28, 330, 756, 1036, 1050, 825, 490, 196, 36, 495, 1200, 1764, 1960, 1750, 1260, 700, 264, 45, 715, 1815, 2820, 3360, 3290, 2695, 1820, 960, 345, 55, 1001, 2640, 4290, 5400, 5670, 5096, 3920, 2520, 1275, 440, 66, 1365, 3718, 6270, 8250, 9150, 8820, 7448, 5460, 3375, 1650, 550, 78
Offset: 1
Examples
Northwest corner: 1....5....15....35....70 3....16...50....120...245 6....34...110...270...560 10...60...200...500..1050
Links
- G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened
Crossrefs
Programs
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Mathematica
f[n_,k_]:=k*(1+k)*(2+k)*n*(1+n)*(10+2*k-n+k*n)/144; TableForm[Table[f[n,k],{n,1,10},{k,1,15}]] Table[f[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten
Formula
T(n,k) = k*(k+1)*(k+2)*n*(n+1)*(k*n-n+2*k+10)/144.
Comments