|
| |
|
|
A088433
|
|
Number of ways to write n as n = u*v*w with 1<=u<=v<w.
|
|
5
| |
|
|
0, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 4, 1, 2, 2, 3, 1, 3, 1, 4, 2, 2, 1, 6, 1, 2, 2, 4, 1, 5, 1, 4, 2, 2, 2, 7, 1, 2, 2, 6, 1, 5, 1, 4, 4, 2, 1, 8, 1, 3, 2, 4, 1, 6, 2, 6, 2, 2, 1, 10, 1, 2, 4, 5, 2, 5, 1, 4, 2, 5, 1, 11, 1, 2, 3, 4, 2, 5, 1, 9, 3, 2, 1, 10, 2, 2, 2, 6, 1, 10, 2, 4, 2, 2, 2, 12, 1, 3, 4, 6
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,6
|
|
|
COMMENTS
| a(n)=1 iff n prime or n prime^2: a(A000430(n))=1.
|
|
|
EXAMPLE
| n=12: (1,1,12), (1,2,6), (1,3,4), (2,2,3): therefore a(12)=4;
n=18: (1,1,18), (1,2,9), (1,3,6): therefore a(18)=3.
|
|
|
CROSSREFS
| Cf. A034836, A088432, A088434.
Sequence in context: A058232 A116933 A194448 * A050334 A161311 A161245
Adjacent sequences: A088430 A088431 A088432 * A088434 A088435 A088436
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 01 2003
|
| |
|
|
