A082506 a(n) = gcd(2^n, n - phi(n)); largest power of 2 dividing cototient(n) = A051953(n).

2, 1, 1, 2, 1, 4, 1, 4, 1, 2, 1, 8, 1, 8, 1, 8, 1, 4, 1, 4, 1, 4, 1, 16, 1, 2, 1, 16, 1, 2, 1, 16, 1, 2, 1, 8, 1, 4, 1, 8, 1, 2, 1, 8, 1, 8, 1, 32, 1, 2, 1, 4, 1, 4, 1, 32, 1, 2, 1, 4, 1, 32, 1, 32, 1, 2, 1, 4, 1, 2, 1, 16, 1, 2, 1, 8, 1, 2, 1, 16, 1, 2, 1, 4, 1, 4, 1, 16, 1, 2, 1, 16, 1, 16, 1, 64, 1, 8, 1

Offset

1,1

Comments

a(n)=1 if and only if n is odd or n = 2. - Robert Israel, May 31 2018

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

Different from A069177, analogous sequence with totient, instead of cototient.

Maple

f:= n -> padic:-ordp(n - numtheory:-phi(n), 2):
map(f, [$1..100]); # Robert Israel, May 31 2018

Crossrefs

Cf. A000010, A051953, A009195, A083250, A007283, A050339, A053576, A069177.

Sequence in context: A113926 A276376 A165585 * A053000 A002070 A326376

Adjacent sequences: A082503 A082504 A082505 * A082507 A082508 A082509

Keyword

nonn

Author

Labos Elemer, Apr 28 2003

Status

approved