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 A235028 #26 Dec 11 2021 04:36:15 %S A235028 0,1,2,3,4,5,6,7,8,9,10,12,14,15,16,17,18,20,21,24,25,27,28,30,31,32, %T A235028 34,35,36,40,42,45,48,49,50,51,54,56,60,62,63,64,68,70,72,73,75,80,81, %U A235028 84,85,90,93,96,98,100,102,105,107,108,112,119,120,124,125 %N A235028 Fixed points of A235027. %C A235028 The first 20 terms are equal with A057890, after which a(21)=25, while A057890(21)=27. On the other hand, 33 is the first term which occurs in A057890 but does not occur here. %C A235028 If terms x and y are included, then also their product x*y is included. If term x is included, then 2^k * x is also included. The sequence contains also all primes in A016041 and their mutual multiples. However, in addition to that, there are also terms like 143 = 11*13, where A235027 will map the factors to each other (as their binary expansions '1011' and '1101' are mirror images of each other), even although neither of them is present in A016041. (These latter kind of primes are in A074832). %C A235028 Please use the "graph" link to see how the terms get rarer. %H A235028 Antti Karttunen, <a href="/A235028/b235028.txt">Table of n, a(n) for n = 1..1897</a> %o A235028 (Scheme, with _Antti Karttunen_'s IntSeq-library) %o A235028 (define A235028 (FIXED-POINTS 1 0 A235027)) %Y A235028 The primes in this sequence: A016041. %Y A235028 Cf. A074832, A235027, A235030, A235145, A057890. %K A235028 nonn,base %O A235028 1,3 %A A235028 _Antti Karttunen_, Jan 02 2014