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 A151823 #6 Jul 22 2025 06:15:39 %S A151823 0,1,2,9,30,213,1757,22956,955569,1853259264 %N A151823 Number of nonequivalent monoids of order n with more than one invertible element. %C A151823 a(n) is also the number of nonequivalent monoids with nontrivial unit group. [From Tom Kelsey (tom(AT)cs.st-and.ac.uk), Apr 01 2010] %H A151823 Andreas Distler and Tom Kelsey, <a href="https://doi.org/10.1007/978-3-540-85110-3_7">The Monoids of Order Eight and Nine</a>, in: Intelligent Computer Mathematics, Lecture Notes in Computer Science, Volume 5144/2008, pp. 61-76, Springer-Verlag. %H A151823 Andreas Distler and Tom Kelsey, <a href="https://doi.org/10.1007/s10472-009-9140-y">The Monoids of Orders Eight, Nine & Ten</a>, Annals of Mathematics and Artificial Intelligence, 56 (2009), 3-25. [From Tom Kelsey (tom(AT)cs.st-and.ac.uk), Apr 01 2010] %Y A151823 Cf. A001423, A058133. %K A151823 nonn %O A151823 1,3 %A A151823 _N. J. A. Sloane_, Jul 10 2009 %E A151823 Definition corrected by Tom Kelsey (tom(AT)cs.st-andrews.ac.uk), Apr 01 2010 %E A151823 Corrected and extended by Tom Kelsey (tom(AT)cs.st-and.ac.uk), Apr 01 2010