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 A127378 #5 Mar 31 2012 13:21:14 %S A127378 0,1,3,2,7,8,6,5,4,17,18,20,22,21,14,15,19,12,13,16,11,10,9,45,46,48, %T A127378 50,49,54,55,61,63,64,57,62,59,58,37,38,39,41,40,51,52,56,31,32,60,34, %U A127378 36,35,42,43,53,28,29,47,33,26,27,44,30,25,24,23,129,130,132,134,133 %N A127378 Signature-permutation of a Catalan automorphism, inverse of A127377. %C A127378 Used to construct A127380. %H A127378 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %o A127378 (Scheme implementation of this automorphism, destructive, that acts on S-expressions, i.e. list-structures:) %o A127378 (define (*A127378! s) (cond ((null? s)) ((null? (cdr s)) (*A069770! s) (*A127378! (cdr s))) ((null? (car s)) (*A069770! s) (*A127380! (car s))) (else (*A127380! s))) s) %Y A127378 Inverse: A127377. A127302(a(n)) = A127302(n) holds for all n. %K A127378 nonn %O A127378 0,3 %A A127378 _Antti Karttunen_, Jan 16 2007