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 A305190 #19 Aug 14 2020 13:31:11 %S A305190 1,1,2,3,6,16,49,232,1351,10367 %N A305190 a(n) is the number of different numbers of Hamiltonian cycles (up to direction) in graphs with n vertices. %H A305190 Erich Friedman, <a href="https://erich-friedman.github.io/mathmagic/0912.html">Math Magic</a> (September 2012) %e A305190 A graph on 4 vertices can have either 0, 1 or 3 Hamiltonian cycles (up to direction), which are 3 numbers, so a(4)= 3. %Y A305190 Cf. A244511. %K A305190 nonn,more %O A305190 1,3 %A A305190 _Johan de Ruiter_, May 27 2018