|
| |
|
|
A090329
|
|
Number of divisors of n that are prefixes of other divisors of n in binary representation.
|
|
1
| |
|
|
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
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,4
|
|
|
COMMENTS
| a(p) = 1 for all primes p;
a(n) = A090330(n) + 1.
|
|
|
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: A077767 A137163 A072625 * A027353 A027352 A029238
Adjacent sequences: A090326 A090327 A090328 * A090330 A090331 A090332
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 26 2003
|
| |
|
|
