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 A083938 #7 Jan 29 2024 07:03:14 %S A083938 0,1,6,42,52,385,414,477,506,555,4089,4180,4388,4479,4645,5095,5186, %T A083938 5394,5485,5651,5969,6060,6226,6502,47363,47661,48366,48664,49237, %U A083938 50800,51098,51803,52101,52674,53808,54106,54679,55681,59311,59609,60314 %N A083938 A014486-indices of binary trees whose left and right subtree are identical. %C A083938 Fixed points of permutation A069770. Diagonal of A072764 (and A072766). %F A083938 a(0)=0, a(n)=A072764bi(n-1, n-1). %Y A083938 a(n) = A080300(A083939(n)). Cf. A083940. %K A083938 nonn %O A083938 0,3 %A A083938 _Antti Karttunen_, May 13 2003