A307313 a(n) is the denominator of n/2^(length of the binary representation of n).

2, 2, 4, 2, 8, 4, 8, 2, 16, 8, 16, 4, 16, 8, 16, 2, 32, 16, 32, 8, 32, 16, 32, 4, 32, 16, 32, 8, 32, 16, 32, 2, 64, 32, 64, 16, 64, 32, 64, 8, 64, 32, 64, 16, 64, 32, 64, 4, 64, 32, 64, 16, 64, 32, 64, 8, 64, 32, 64, 16, 64, 32, 64, 2, 128, 64, 128, 32, 128, 64

Offset: 1

Author

Michel Marcus, Apr 02 2019

Keywords

• nonn
• base
• frac

Examples

			For n=1, 1 = 1_2,  a(1) = denominator(1/(2^1)) = denominator(1/2) = 2;
For n=2, 2 = 10_2, a(2) = denominator(2/(2^2)) = denominator(1/2) = 2;
For n=3, 3 = 11_2, a(3) = denominator(3/(2^2)) = denominator(3/4) = 4.
		

Crossrefs

Cf. A062383, A070939, A000265 (numerators), A078267 (analog in base 10).

Programs

PARI

a(n) = denominator(n/(2^(#binary(n))));

Formula

a(n) = denominator(n/2^A070939(n)).

a(n) = denominator(n/A062383(n)).

a(n) = 2^A070940(n).