A353754 - OEIS

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A353754

Greatest common divisor of phi(sigma(n)) and Product_{p^e||n} phi(sigma(p^e)), where n = Product_{p^e||n}, with each p^e the maximal power of prime p that divides n.

1, 2, 2, 6, 2, 4, 4, 8, 12, 2, 4, 12, 6, 8, 4, 30, 6, 24, 8, 12, 8, 4, 8, 16, 30, 12, 16, 24, 8, 8, 16, 36, 8, 6, 8, 72, 18, 16, 12, 8, 12, 16, 20, 24, 24, 8, 16, 60, 36, 60, 12, 6, 18, 32, 8, 32, 16, 8, 16, 24, 30, 32, 48, 126, 12, 16, 32, 36, 16, 16, 24, 96, 36, 36, 60, 48, 16, 24, 32, 60, 110, 12, 24, 48, 12, 40

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OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to sigma(n)

FORMULA

a(n) = gcd(A062401(n), A353752(n)) = gcd(A062401(n), A353753(n)) = gcd(A353752(n), A353753(n)).

a(n) = A062401(n) / A353755(n) = A353752(n) / A353756(n).

PROG

(PARI)

A062401(n) = eulerphi(sigma(n));