This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A185781 #10 Jul 13 2017 03:07:35
%S A185781 1,5,2,14,12,3,30,36,21,4,55,80,66,32,5,91,150,150,104,45,6,140,252,
%T A185781 285,240,150,60,7,204,392,483,460,350,204,77,8,285,576,756,784,675,
%U A185781 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
%N A185781 Accumulation array of A185780, by antidiagonals.
%C A185781 See A144112 and A185780.
%H A185781 G. C. Greubel, <a href="/A185781/b185781.txt">Table of n, a(n) for the first 50 rows, flattened</a>
%F A185781 T(n,k) = k*(k+1)*n*(k*n-n+k+2)/6, k>=1, n>=1.
%e A185781 Northwest corner:
%e A185781 1.....5....14....30....55
%e A185781 2.....12...36....80....150
%e A185781 3.....21...66....150...285
%e A185781 4.....32...104...240...460
%e A185781 5.....45...150...350...675
%t A185781 (See A185780.)
%t A185781 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 *)
%Y A185781 Cf. A144112, A185780.
%Y A185781 Columns 1 to 4: A000027, A028347, 2*A033537, 10*A005563.
%K A185781 nonn,tabl
%O A185781 1,2
%A A185781 _Clark Kimberling_, Feb 03 2011