|
Search: id:A134612
|
|
|
| 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)). |
|
+0
7
|
|
| 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; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
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.
Adjacent sequences: A134609 A134610 A134611 this_sequence A134613 A134614 A134615
Sequence in context: A134600 A134601 A134611 this_sequence A025475 A125643 A002760
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), Nov 112007
|
|
|
Search completed in 0.002 seconds
|
