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 A323663 #18 Jan 23 2019 10:10:12 %S A323663 1,1,3,1,7,6,1,21,22,10,1,71,105,50,15,1,253,566,325,95,21,1,925,3256, %T A323663 2386,780,161,28,1,3433,19489,18760,7231,1596,252,36,1,12871,119713, %U A323663 154085,71890,17857,2926,372,45,1,48621,748342,1303753,747860,214396,38332,4950,525,55 %N A323663 Square array A(n,k), n >= 1, k >= 1, read by antidiagonals, where A(n,k) is Sum_{j=1..n} binomial(j*k, k). %H A323663 Seiichi Manyama, <a href="/A323663/b323663.txt">Antidiagonals n = 1..140, flattened</a> %e A323663 Square array begins: %e A323663 1, 1, 1, 1, 1, 1, ... %e A323663 3, 7, 21, 71, 253, 925, ... %e A323663 6, 22, 105, 566, 3256, 19489, ... %e A323663 10, 50, 325, 2386, 18760, 154085, ... %e A323663 15, 95, 780, 7231, 71890, 747860, ... %e A323663 21, 161, 1596, 17857, 214396, 2695652, ... %e A323663 28, 252, 2926, 38332, 539028, 7941438, ... %e A323663 36, 372, 4950, 74292, 1197036, 20212950, ... %Y A323663 Columns 1-3 give A000217, A002412, A116689. %Y A323663 Rows 1-3 give A000012, A244174, A029848. %Y A323663 Main diagonal is A096131. %Y A323663 Cf. A060539. %K A323663 nonn,tabl %O A323663 1,3 %A A323663 _Seiichi Manyama_, Jan 23 2019