A345937 a(n) = gcd(n-1, uphi(n)), where uphi is unitary totient (or unitary phi) function, A047994.

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

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

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

Cf. A047994, A345938, A345939.

Cf. also A049559, A340087, A323409, A345947.

Sequence in context: A350778 A001438 A342410 * A105587 A345998 A319676

Adjacent sequences: A345934 A345935 A345936 * A345938 A345939 A345940

Keyword

nonn

Author

Antti Karttunen, Jun 29 2021

Status

approved