cp's OEIS Frontend

A320113 Filter sequence for counting the residue classes mod 12 of divisors of n.

%I A320113 #7 Oct 08 2018 08:09:26
%S A320113 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,5,17,7,18,19,20,11,21,22,23,
%T A320113 24,25,5,26,7,27,28,10,29,30,13,14,31,32,5,33,7,34,35,20,11,36,37,38,
%U A320113 15,39,5,40,29,41,19,10,11,42,13,14,43,44,45,46,7,18,28,47,11,48,13,23,49,25,29,50,7,51,52,10,11,53,45,14,15,54,5,55,56,34,19,20,29,57,13,58,59,60,5
%N A320113 Filter sequence for counting the residue classes mod 12 of divisors of n.
%C A320113 Restricted growth sequence transform of A320112.
%C A320113 For all i, j:
%C A320113   a(i) = a(j) => A320115(i) = A320115(j).
%C A320113   a(i) = a(j) => A320117(i) = A320117(j).
%H A320113 Antti Karttunen, <a href="/A320113/b320113.txt">Table of n, a(n) for n = 1..100000</a>
%o A320113 (PARI)
%o A320113 up_to = 100000;
%o A320113 A320112(n) = { my(m=1); fordiv(n,d,if(d>1, m *= prime(1+(d%12)))); (m); };
%o A320113 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 A320113 v320113 = rgs_transform(vector(up_to,n,A320112(n)));
%o A320113 A320113(n) = v320113[n];
%Y A320113 Cf. A320109, A320112, A320115, A320117.
%K A320113 nonn
%O A320113 1,2
%A A320113 _Antti Karttunen_, Oct 06 2018