|
| |
|
|
A134612
|
|
Nonprime numbers such that the cube mean of their prime factors is a prime (where the cube mean of c and d is ((c^3+d^3)/2)^(1/3)).
|
|
6
| |
|
|
1, 4, 8, 9, 16, 25, 27, 32, 49, 64, 81, 121, 125, 128, 169, 243, 256, 289, 343, 361, 512, 529, 625, 729, 841, 961, 1024, 1331, 1369, 1681, 1849, 2048, 2187, 2197, 2209, 2401, 2809, 3125, 3481, 3721, 4096, 4489, 4913, 5041, 5329, 6241, 6561, 6859, 6889, 7921
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| All perfect prime powers (A025475) are included.
|
|
|
EXAMPLE
| a(5)=25, since 25=5*5 and ((5^3+5^3)/2)^(1/3)=5.
|
|
|
CROSSREFS
| Cf. A001597, A025475, A134333, A134344, A134376.
Cf. A134600, A134602, A134605, A134614, A134617, A134619, A134621.
Sequence in context: A134600 A134601 A134611 * A025475 A195942 A125643
Adjacent sequences: A134609 A134610 A134611 * A134613 A134614 A134615
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), Nov 11 2007
|
| |
|
|
