A090329 Number of divisors of n that are prefixes of other divisors of n in binary representation.

0, 1, 1, 2, 1, 2, 1, 3, 1, 3, 1, 4, 1, 2, 2, 4, 1, 4, 1, 4, 2, 3, 1, 6, 1, 2, 2, 4, 1, 5, 1, 5, 1, 3, 1, 7, 1, 3, 2, 6, 1, 5, 1, 4, 3, 3, 1, 8, 1, 4, 2, 4, 1, 6, 2, 6, 2, 2, 1, 8, 1, 2, 3, 6, 1, 5, 1, 5, 1, 5, 1, 9, 1, 3, 2, 5, 1, 6, 1, 8, 2, 3, 1, 8, 2, 3, 2, 6, 1, 7, 1, 4, 2, 3, 2, 10, 1, 3, 2, 6, 1, 6

Offset

1,4

Comments

a(p) = 1 for all primes p;

a(n) = A090330(n) + 1.

Links

Table of n, a(n) for n=1..102.

Example

Divisors of n=35: {1,5,7,35}, in binary {1,101,111,100011}: as
only '1' is a prefex, a(35)=1;
divisors of n=45: {1,3,5,9,15,45}, in binary
{1,11,101,1001,1111,101101}: '1' is a prefex of all other divisors, '11' of
'1111' and '101' of '101101', therefore a(45)=3.

Crossrefs

Cf. A000005.

Sequence in context: A278538 A282903 A332677 * A224876 A340830 A027353

Adjacent sequences: A090326 A090327 A090328 * A090330 A090331 A090332

Keyword

nonn

Author

Reinhard Zumkeller, Nov 26 2003

Status

approved