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A323163 Greatest common divisor of product (1+(p^e)) and product p^(e-1), where p ranges over prime factors of n, with e corresponding exponent; a(n) = gcd(A034448(n), A003557(n)). 4

%I #7 Jan 09 2019 21:22:53

%S 1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,3,1,2,1,1,1,4,1,1,1,2,1,1,1,1,1,1,

%T 1,2,1,1,1,2,1,1,1,2,3,1,1,4,1,1,1,2,1,3,1,4,1,1,1,2,1,1,1,1,1,1,1,2,

%U 1,1,1,6,1,1,1,2,1,1,1,2,1,1,1,2,1,1,1,4,1,3,1,2,1,1,1,4,1,1,3,10,1,1,1,2,1

%N Greatest common divisor of product (1+(p^e)) and product p^(e-1), where p ranges over prime factors of n, with e corresponding exponent; a(n) = gcd(A034448(n), A003557(n)).

%H Antti Karttunen, <a href="/A323163/b323163.txt">Table of n, a(n) for n = 1..65537</a>

%F a(n) = gcd(A003557(n), A034448(n)).

%o (PARI)

%o A003557(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); };

%o A034448(n) = { my(f=factorint(n)); prod(k=1, #f~, 1+(f[k, 1]^f[k, 2])); }; \\ After code in A034448

%o A323163(n) = gcd(A003557(n), A034448(n));

%Y Cf. A003557, A034448, A322318, A323159.

%Y Differs from A062760 for the first time at n=36, where a(36) = 2, while A062760(36) = 1.

%K nonn

%O 1,12

%A _Antti Karttunen_, Jan 09 2019

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Last modified April 19 14:10 EDT 2024. Contains 371792 sequences. (Running on oeis4.)