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 A057279 #15 May 30 2022 18:03:18 %S A057279 1,0,1,1,0,0,3,4,4,1,1,0,0,0,7,21,37,47,38,27,13,5,1,1,0,0,0,0,18,90, %T A057279 309,661,1125,1477,1665,1489,1154,707,379,154,61,16,5,1,1,0,0,0,0,0, %U A057279 44,374,1981,7107,19166,41867,77194,122918,170308,206980,220768,207301,171008,124110,78813,43862,21209,8951,3242,1043,288,76,17,5,1,1 %N A057279 Triangle T(n,k) of number of digraphs with a quasi-source on n unlabeled nodes and with k arcs, k = 0..n*(n-1). %H A057279 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a234/A234007.java">Java program</a> (github) %H A057279 V. Jovovic and G. Kilibarda, <a href="http://dx.doi.org/10.1016/S0012-365X(00)00112-6">Enumeration of labeled quasi-initially connected digraphs</a>, Discrete Math., 224 (2000), 151-163. %e A057279 Table starts: %e A057279 [1], %e A057279 [0,1,1], %e A057279 [0,0,3,4,4,1,1], %e A057279 [0,0,0,7,21,37,47,38,27,13,5,1,1], %e A057279 ... %e A057279 Number of digraphs with a quasi-source on 3 unlabeled nodes is 13=3+4+4+1+1. %Y A057279 Row sums give A049512. Cf. A057270-A057278. %K A057279 nonn,tabf %O A057279 1,7 %A A057279 _Vladeta Jovovic_, Goran Kilibarda, Sep 14 2000 %E A057279 More terms from _Sean A. Irvine_, May 30 2022