cp's OEIS Frontend

A330750 Lexicographically earliest infinite sequence such that a(i) = a(j) => A319626(i) = A319626(j) for all i, j.

%I A330750 #8 Dec 29 2019 19:35:39
%S A330750 1,2,3,4,5,3,6,7,8,9,10,11,12,13,5,14,15,8,16,17,18,19,20,21,22,23,24,
%T A330750 25,26,5,27,28,29,30,6,8,31,32,33,34,35,18,36,37,38,39,40,41,42,43,44,
%U A330750 45,46,24,47,48,49,50,51,9,52,53,54,55,56,29,57,58,59,13,60,61,62,63,22,64,10,33,65,66,67,68,69,70,71,72,73,74,75,38,76
%N A330750 Lexicographically earliest infinite sequence such that a(i) = a(j) => A319626(i) = A319626(j) for all i, j.
%C A330750 Restricted growth sequence transform of A319626, where A319626(n) = n / A330749(n) = n / gcd(n, A064989(n)).
%H A330750 Antti Karttunen, <a href="/A330750/b330750.txt">Table of n, a(n) for n = 1..65537</a>
%o A330750 (PARI)
%o A330750 up_to = 65537;
%o A330750 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 A330750 A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
%o A330750 A319626(n) = (n / gcd(n, A064989(n)));
%o A330750 v330750 = rgs_transform(vector(up_to, n, A319626(n)));
%o A330750 A330750(n) = v330750[n];
%Y A330750 Cf. A064989, A319626, A330749.
%K A330750 nonn
%O A330750 1,2
%A A330750 _Antti Karttunen_, Dec 29 2019