A318987 Number of semigroups of order n without identity.
1, 0, 3, 17, 153, 1687, 26397, 1596113, 3682361420
Offset: 0
Extensions
More terms from Joerg Arndt, Dec 09 2018
a(0) prepended by Jianing Song, Oct 26 2019
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.