cp's OEIS Frontend

A331286 Odd part of number of divisors of primorial inflation of n: a(n) = A000265(A329605(n)).

%I A331286 #10 Jan 14 2020 22:19:17
%S A331286 1,1,1,3,1,3,1,1,9,3,1,1,1,3,9,5,1,3,1,1,9,3,1,5,27,3,1,1,1,3,1,3,9,3,
%T A331286 27,15,1,3,9,5,1,3,1,1,1,3,1,3,81,9,9,1,1,5,27,5,9,3,1,15,1,3,1,7,27,
%U A331286 3,1,1,9,9,1,9,1,3,3,1,81,3,1,3,25,3,1,15,27,3,9,5,1,5,81,1,9,3,27,7,1,27,1,45,1,3,1,5,3
%N A331286 Odd part of number of divisors of primorial inflation of n: a(n) = A000265(A329605(n)).
%H A331286 Antti Karttunen, <a href="/A331286/b331286.txt">Table of n, a(n) for n = 1..10000</a>
%H A331286 Antti Karttunen, <a href="/A331286/a331286.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%F A331286 a(n) = A000265(A329605(n)).
%F A331286 a(n) = A212181(A108951(n)).
%o A331286 (PARI) A331286(n) = if(1==n,1,my(f=factor(n),e=1,m=1); forstep(i=#f~,1,-1, e += f[i,2]; m *= (e>>valuation(e,2))^(primepi(f[i,1])-if(1==i,0,primepi(f[i-1,1])))); (m));
%Y A331286 Cf. A000265, A108951, A212181, A329605.
%Y A331286 Cf. also A322865.
%K A331286 nonn
%O A331286 1,4
%A A331286 _Antti Karttunen_, Jan 14 2020