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 A308500 #23 May 12 2021 03:56:21
%S A308500 1,1,2,1,2,3,1,2,4,4,1,2,8,8,5,1,2,22,32,16,6,1,2,72,170,128,32,7,1,2,
%T A308500 254,992,1366,512,64,8,1,2,926,6008,16512,10922,2048,128,9,1,2,3434,
%U A308500 37130,215766,261632,87382,8192,256,10,1,2,12872,232562,2973350,6643782,4196352,699050,32768,512,11
%N A308500 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals: A(n,k) = Sum_{j=0..n} binomial(k*n,k*j).
%H A308500 Seiichi Manyama, <a href="/A308500/b308500.txt">Antidiagonals n = 0..115, flattened</a>
%e A308500 Square array begins:
%e A308500 1, 1, 1, 1, 1, 1, ...
%e A308500 2, 2, 2, 2, 2, 2, ...
%e A308500 3, 4, 8, 22, 72, 254, ...
%e A308500 4, 8, 32, 170, 992, 6008, ...
%e A308500 5, 16, 128, 1366, 16512, 215766, ...
%e A308500 6, 32, 512, 10922, 261632, 6643782, ...
%e A308500 7, 64, 2048, 87382, 4196352, 215492564, ...
%t A308500 T[n_, k_] := Sum[Binomial[k*n, k*j], {j, 0, n}] ; Table[T[k, n - k], {n, 0, 10}, {k, 0, n}] // Flatten (* _Amiram Eldar_, May 12 2021 *)
%Y A308500 Columns k=0..10 give A000027(n+1), A000079, A081294, A007613, A070775, A070782, A070967, A094211, A070832, A094213, A070833.
%Y A308500 Main diagonal gives A167009.
%K A308500 nonn,tabl
%O A308500 0,3
%A A308500 _Seiichi Manyama_, Jun 01 2019