|
| |
|
|
A080403
|
|
Numbers n such that both A000213(n) and A001157(n) are squarefree: sum of divisors and squares of divisors of n are squarefree.
|
|
0
| |
|
|
1, 2, 4, 5, 8, 9, 13, 16, 18, 20, 25, 29, 37, 49, 50, 61, 64, 72, 73, 80, 101, 109, 113, 116, 117, 121, 122, 128, 137, 144, 148, 169, 173, 181, 200, 208, 218, 229, 242, 244, 261, 277, 281, 289, 292, 313, 317, 320, 325, 333, 353, 362, 373, 389, 397, 401, 404, 409
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
MATHEMATICA
| Do[s1=MoebiusMu[DivisorSigma[1, n]]; s2=MoebiusMu[DivisorSigma[2, n]]; If[ !Equal[s1, 0]&&!Equal[s2, 0], Print[n]], {n, 1, 1000}]
|
|
|
CROSSREFS
| Cf. A001157, A000213, A065300, A080401, A080402.
Sequence in context: A143989 A064573 A065300 * A195364 A200947 A092739
Adjacent sequences: A080400 A080401 A080402 * A080404 A080405 A080406
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Mar 19 2003
|
| |
|
|
