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 A366880 #7 Oct 27 2023 16:39:56 %S A366880 1,2,3,4,3,5,6,7,3,3,7,8,3,9,10,11,3,3,3,3,3,12,13,14,3,15,16,17,3,18, %T A366880 19,20,3,3,3,3,3,3,3,3,3,21,22,23,3,24,25,26,3,3,27,28,3,29,30,31,3, %U A366880 32,33,34,3,17,9,25,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,35,36,3,37,38,39,3,40,41,42,3,43 %N A366880 Lexicographically earliest infinite sequence such that a(i) = a(j) => A366879(i) = A366879(j) for all i, j >= 0. %C A366880 Restricted growth sequence transform of A366879. %H A366880 Antti Karttunen, <a href="/A366880/b366880.txt">Table of n, a(n) for n = 0..65537</a> %H A366880 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %o A366880 (PARI) %o A366880 up_to = 65537; %o A366880 rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; }; %o A366880 A163511(n) = if(!n, 1, my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p)); %o A366880 A326938(n) = sumdiv(n, d, if(n/d%2, moebius(n/d)*moebius(d)*d)); %o A366880 A366879(n) = A326938(A163511(n)); %o A366880 v366880 = rgs_transform(vector(1+up_to,n,A366879(n-1))); %o A366880 A366880(n) = v366880[1+n]; %Y A366880 Cf. A002131, A163511, A326938, A366879. %Y A366880 Cf. also A366878. %K A366880 nonn %O A366880 0,2 %A A366880 _Antti Karttunen_, Oct 27 2023