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 A342533 #18 Oct 07 2022 09:09:36 %S A342533 1,2,4,11,24,81,193,772,1920,8735,23040 %N A342533 a(n) is the number of n-gons in A000940 that display symmetry (reflection / rotation). %F A342533 a(p) = (2^((p-1)/2)*((p-1)/2)!)/2 for prime p. %e A342533 Of the A000940(6)=12 hexagons, 11 have symmetry and 1 is asymmetric, so a(6)=11. %Y A342533 Cf. A000940. %K A342533 nonn,more %O A342533 3,2 %A A342533 _Ian Mooney_, Mar 14 2021