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 A057276 #11 Jan 14 2022 15:32:27
%S A057276 1,0,0,1,0,0,0,1,2,1,1,0,0,0,0,1,4,16,22,22,11,5,1,1,0,0,0,0,0,1,7,58,
%T A057276 240,565,928,1065,953,640,359,150,59,16,5,1,1,0,0,0,0,0,0,1,10,165,
%U A057276 1281,6063,19591,47049,87690,131927,163632,170720,151238,115122,75357,42745,20891,8877,3224,1039,286,76,17,5,1,1
%N A057276 Triangle T(n,k) of number of strongly connected digraphs on n unlabeled nodes and with k arcs, k=0..n*(n-1).
%H A057276 Andrew Howroyd, <a href="/A057276/b057276.txt">Table of n, a(n) for n = 1..2680</a> (rows 1..20)
%e A057276 Triangle begins:
%e A057276 [1] 1;
%e A057276 [2] 0,0,1;
%e A057276 [3] 0,0,0,1,2,1,1;
%e A057276 [4] 0,0,0,0,1,4,16,22,22,11,5,1,1;
%e A057276 ...
%e A057276 The number of strongly connected digraphs on 3 unlabeled nodes is 5 = 1+2+1+1.
%o A057276 (PARI) \\ See PARI link in A350489 for program code.
%o A057276 { my(A=A057276rows(5)); for(n=1, #A, print(A[n])) } \\ _Andrew Howroyd_, Jan 13 2022
%Y A057276 Row sums give A035512.
%Y A057276 Column sums give A350752.
%Y A057276 The labeled version is A057273.
%Y A057276 Cf. A054733, A057270, A057277, A057278, A057279, A350489.
%K A057276 nonn,tabf
%O A057276 1,9
%A A057276 _Vladeta Jovovic_, Goran Kilibarda, Sep 14 2000
%E A057276 Terms a(46) and beyond from _Andrew Howroyd_, Jan 13 2022