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URL: https://oeis.org/A345937

⇱ A345937 - OEIS

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A345937
a(n) = gcd(n-1, uphi(n)), where uphi is unitary totient (or unitary phi) function, A047994.
4
1, 1, 2, 3, 4, 1, 6, 7, 8, 1, 10, 1, 12, 1, 2, 15, 16, 1, 18, 1, 4, 1, 22, 1, 24, 1, 26, 9, 28, 1, 30, 31, 4, 1, 2, 1, 36, 1, 2, 1, 40, 1, 42, 1, 4, 1, 46, 1, 48, 1, 2, 3, 52, 1, 2, 1, 4, 1, 58, 1, 60, 1, 2, 63, 16, 5, 66, 1, 4, 3, 70, 1, 72, 1, 2, 3, 4, 1, 78, 1, 80, 1, 82, 1, 4, 1, 2, 1, 88, 1, 18, 1, 4, 1, 2, 1, 96
OFFSET
1,3
LINKS
FORMULA
a(n) = gcd(n-1, A047994(n)).
a(n) = A047994(n) / A345938(n).
a(n) = (n-1) / A345939(n), for n > 1.
a(2n-1) = A345947(2n-1), for n >= 1.
PROG
(PARI)
A047994(n) = { my(f=factor(n)~); prod(i=1, #f, (f[1, i]^f[2, i])-1); };
A345937(n) = gcd(n-1, A047994(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 29 2021
STATUS
approved