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 A305606 #11 Apr 26 2023 07:07:39 %S A305606 0,1,0,2,2,5,6,23,45,138,347,1007,2751,7998,22638,65708,189505,551798, %T A305606 1606383,4697905 %N A305606 Number of blunt polytans (polyaboloes) with n cells, identifying mirror images. A blunt polytan is one with no acute corners. %H A305606 George Sicherman, <a href="https://sicherman.net/blunt/blunt.html">Catalogue of Blunt Polytans</a> %e A305606 There are 3 ditans. Only the square ditan lacks acute corners, so a(2)=1. %Y A305606 Cf. A006074, number of polyaboloes with n cells, identifying mirror images. %K A305606 nonn,hard,more %O A305606 1,4 %A A305606 _George Sicherman_, Jun 05 2018 %E A305606 a(15)-a(20) from _John Mason_, Jan 07 2022