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 A129675 #15 Mar 18 2022 21:51:57
%S A129675 3,2,1,5,7,4,6,9,15,8,11,10,12,14,13,17,21,16,19,18,20,23,27,22,24,26,
%T A129675 25,29,31,28,30,33,37,32,35,34,36,39,43,38,40,42,41,45,51,44,47,46,48,
%U A129675 50,49,53,55,52,54,57,63,56,59,58,60,62,61,65,69,64,67,66,68,71,75,70
%N A129675 Inverse permutation to A129674.
%C A129675 The inversion maintains the cyclic characteristics as described in A129674.
%H A129675 Ferenc Adorjan, <a href="/A129675/b129675.txt">Table of n, a(n) for n = 1..10000</a>
%H A129675 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%o A129675 (PARI) {pinverse(v)= /* Permutation inverse of a positive sequence */
%o A129675 local(n,m,x);n=matsize(v)[2]; x=vector(n);
%o A129675 for(i=1,n,if(v[i]<=n,x[v[i]]=i)); return(x)}
%o A129675 a=pinverse(A129674)
%Y A129675 Inverse of A129674, Cf. A128754, A128755, A129679 and A001969.
%K A129675 nonn,base
%O A129675 1,1
%A A129675 Ferenc Adorjan (fadorjan(AT)freemail.hu or ferencadorjan(AT)gmail.com), May 01 2007