A360868 Number of unlabeled connected loopless multigraphs with circuit rank n and degree >= 3 at each node.
0, 1, 4, 23, 172, 1848, 25684
Offset: 1
Formula
a(n) = Sum_{k>=1} A360866(n + k - 1, k).
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.