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 A289157 #27 Jun 02 2025 17:24:47
%S A289157 1,1,4,9,37,146,772,4449,30307,228605,1921464,17652327,176162548,
%T A289157 1893738334,21806975279,267636988052,3486370839295,48029272657002,
%U A289157 697542580286159,10649954607360119,170508064788069346,2856122791685125616,49951625299057923405
%N A289157 Number of unlabeled connected loopless multigraphs with n nodes of degree 4 or less.
%o A289157 (nauty) geng -c -D4 ${n} -q | multig -D4 -u
%Y A289157 Column k=4 of A334546.
%Y A289157 Cf. A121941 (single edges only), A134818 (with no more than triple edges), A289158 (with no more than double edges).
%Y A289157 Cf. A243391 (degree 3 or less).
%K A289157 nonn
%O A289157 0,3
%A A289157 _Natan Arie Consigli_, Jul 04 2017
%E A289157 a(18)-a(22) from _Andrew Howroyd_, Mar 20 2020