cp's OEIS Frontend

A319343 Filter sequence combining the prime signature of phi(d) from all proper divisors d of n.

%I A319343 #6 Sep 17 2018 15:45:33
%S A319343 1,2,2,3,2,4,2,4,5,6,2,7,2,8,9,10,2,11,2,12,13,8,2,14,15,16,13,17,2,
%T A319343 18,2,19,13,20,21,22,2,16,23,24,2,25,2,17,26,8,2,27,28,29,30,31,2,25,
%U A319343 21,32,23,16,2,33,2,34,35,36,37,25,2,38,13,39,2,40,2,41,42,31,43,44,2,45,46,47,2,48,49,34,23,32,2,50,51,17,52,8,37,53,2,54,35
%N A319343 Filter sequence combining the prime signature of phi(d) from all proper divisors d of n.
%C A319343 Restricted growth sequence transform of A319342.
%H A319343 Antti Karttunen, <a href="/A319343/b319343.txt">Table of n, a(n) for n = 1..65537</a>
%o A319343 (PARI)
%o A319343 up_to = 65537;
%o A319343 A319342(n) = { my(m=1); fordiv(n, d, if((d<n), m *= prime(A318881(d)))); (m); }; \\ Needs also code from A318881
%o A319343 v319343 = rgs_transform(vector(up_to,n,A319342(n)));
%o A319343 A319343(n) = v319343[n];
%Y A319343 Cf. A318881, A319342, A319345.
%Y A319343 Cf. also A305983.
%K A319343 nonn
%O A319343 1,2
%A A319343 _Antti Karttunen_, Sep 17 2018