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 A127307 #5 Jul 07 2025 16:13:30 %S A127307 3,6,7,14,15,16,17,18,37,38,39,40,41,42,43,44,45,46,47,48,49,50,107, %T A127307 108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124, %U A127307 125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141 %N A127307 Positions of Dyck words beginning as UUD (110) in A014486/A063171. %F A127307 a(n) = A072764bi(A072795(A072771(n)),A072772(n)). %o A127307 (Scheme) (define (A127307 n) (A072764bi (A072795 (A072771 n)) (A072772 n))) %o A127307 (define (*A127307 s) (cons (cons '() (car s)) (cdr s))) ;; Corresponding function acting on S-expressions. %K A127307 nonn %O A127307 1,1 %A A127307 _Antti Karttunen_, Jan 16 2007