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A343223
a(n) = gcd(A003415(n), A003415(sigma(n))-n), where A003415 is the arithmetic derivative, and sigma is the sum of divisors of n.
6
1, 1, 1, 1, 1, 5, 1, 12, 2, 1, 1, 4, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 4, 2, 15, 1, 32, 1, 1, 1, 1, 1, 1, 1, 4, 1, 3, 1, 1, 1, 1, 1, 16, 13, 5, 1, 16, 1, 1, 5, 1, 1, 1, 1, 4, 1, 1, 1, 4, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 16, 3, 1, 1, 1, 1, 1, 1, 4, 1, 3, 1, 4, 1, 3, 1, 48, 1, 1, 1, 8, 1, 1, 1, 2, 1, 1, 1, 1, 1
OFFSET
1,6
FORMULA
a(n) = gcd(A003415(n), A342926(n)).
PROG
(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A342926(n) = (A003415(sigma(n))-n);
A343223(n) = gcd(A003415(n), A342926(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 15 2021
STATUS
approved