A340147 - OEIS

%I #10 Dec 30 2020 20:00:23

%S 1,1,1,3,1,2,1,9,5,3,1,3,1,5,6,27,1,10,1,9,10,6,1,18,7,8,25,15,1,3,1,

%T 81,3,9,15,15,1,11,4,27,1,5,1,9,10,14,1,27,11,21,18,6,1,50,2,45,22,15,

%U 1,18,1,18,50,243,24,12,1,27,7,3,1,90,1,20,21,33,30,16,1,81,125,21,1,30,3,23,30,54,1,15,40,21

%N a(n) = A247074(A003961(n)).

%C Prime shifted analog of A247074.

%C Each term a(n) is a divisor of A340072(n).

%H Antti Karttunen, <a href="/A340147/b340147.txt">Table of n, a(n) for n = 1..8191</a>

%H Antti Karttunen, <a href="/A340147/a340147.txt">Data supplement: n, a(n) computed for n = 1..65537</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%F a(n) = A247074(A003961(n)).

%F a(n) = A003972(n) / A340148(n).

%o (PARI)

%o A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };

%o A247074(n) = { my(f=factor(n)); eulerphi(f)/prod(i=1, #f~, gcd(f[i, 1]-1, n-1)); }; \\ From A247074

%o A340147(n) = A247074(A003961(n));

%Y Cf. A003961, A003972, A247074, A340072, A340148, A340149 (odd part).

%K nonn

%O 1,4

%A _Antti Karttunen_, Dec 30 2020