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A082506
a(n) = gcd(2^n, n - phi(n)); largest power of 2 dividing cototient(n) = A051953(n).
1
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
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
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 28 2003
STATUS
approved