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 A054427 #12 Dec 13 2021 03:03:52 %S A054427 1,2,4,3,8,5,16,7,6,9,32,17,64,15,13,12,10,33,128,14,11,65,256,31,25, %T A054427 24,18,129,512,29,20,257,1024,63,30,28,49,48,21,19,34,513,2048,26,23, %U A054427 1025,4096,127,61,57,27,97,96,22,40,36,66,2049,8192,62,56,41,35,4097 %N A054427 Permutation of natural numbers: maps the fractions A038567/A038566 to the right side (n/m > 1) of Stern-Brocot tree. %H A054427 <a href="/index/St#Stern">Index entries for sequences related to Stern's sequences</a> %H A054427 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A054427 Right side of Stern-Brocot tree: 1/1 2/1 3/2 3/1 4/3 5/3 5/2 4/1 5/4 7/5 8/5 7/4 7/3 8/3 7/2 5/1 %e A054427 A038567/A038566: 1/1 2/1 3/1 3/2 4/1 4/3 5/1 5/2 5/3 5/4 6/1 6/5 7/1 7/2 7/3 7/4 %p A054427 A038567_A038566_to_SternBrocot_permutation := proc(u) local a,n,i; a := []; for n from 1 to u do for i from 1 to n do if (1 = igcd(n,i)) then a := [op(a),cfrac2binexp(convert((n/i),confrac))+1]; fi; od; od; RETURN(a); end; # cfrac2binexp given in A054424. %Y A054427 A038567/A038566 = shift_left(A007306)/A047679(A054427(.)). %Y A054427 Inverse permutation: A054428. %K A054427 nonn %O A054427 1,2 %A A054427 _Antti Karttunen_