A058110 Semigroups of order n with 2 idempotents.
3, 9, 50, 309, 2806, 58583
Offset: 2
Crossrefs
Column 2 of A058108.
Extensions
Updated Feb 19 2001
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.