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 A329904 #9 Dec 24 2019 17:31:17
%S A329904 1,1,2,2,3,4,5,6,4,7,3,8,9,10,11,12,13,14,15,6,16,9,5,17,18,19,20,21,
%T A329904 22,23,24,25,26,27,28,29,30,11,31,32,8,33,13,7,34,35,36,37,38,39,40,
%U A329904 41,42,22,43,44,45,46,47,48,49,50,51,52,53,54,55,56,15,57,58,20,12,59,60,61,17,62,10,63,64,65,66,67,68,69
%N A329904 Position of A329899(n) in A025487.
%C A329904 Restricted growth sequence transform of A329899.
%C A329904 Each positive natural number occurs exactly twice.
%C A329904 For all i, j > 1:
%C A329904 a(i) = a(j) => A329907(i) = A329907(j).
%H A329904 Antti Karttunen, <a href="/A329904/b329904.txt">Table of n, a(n) for n = 1..10000</a>
%F A329904 a(n) = A085089(A329899(n)).
%o A329904 (PARI) A329904(n) = { my(k=A329899(n)); for(i=1,oo,if(A025487(i)==k,return(i))); };
%Y A329904 Cf. A025487, A085089, A329899, A329905, A329907.
%K A329904 nonn
%O A329904 1,3
%A A329904 _Antti Karttunen_, Dec 24 2019