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 A361480 #18 Mar 30 2023 15:28:38 %S A361480 0,1,2,3,6,5,6,7,14,13,10,13,12,13,14,15,30,29,26,27,26,21,26,29,28, %T A361480 27,26,27,28,29,30,31,62,61,58,59,54,53,54,59,58,53,42,53,54,53,58,61, %U A361480 60,59,54,51,54,53,54,59,56,59,58,59,60,61,62,63,126,125 %N A361480 a(n) is the greatest integer whose binary expansion has the same multiset of run-lengths as that of n. %H A361480 Rémy Sigrist, <a href="/A361480/b361480.txt">Table of n, a(n) for n = 0..8191</a> %H A361480 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %F A361480 a(a(n)) = a(n). %F A361480 a(n) >= n. %o A361480 (PARI) a(n) = { my (r=[]); while (n, my (v=valuation(n+n%2, 2)); n\=2^v; r=concat(v, r)); r=vecsort(r); my (h=0, t=#r+1, v=0); for (k=1, #r, v=(v+k%2)*2^if (k%2, r[t--], r[h++])-k%2;); return (v); } %Y A361480 Cf. A073138, A335835, A361478, A361479. %K A361480 nonn,look,base %O A361480 0,3 %A A361480 _Rémy Sigrist_, Mar 13 2023