|
| |
|
|
A075539
|
|
Perfect powers n such that (n-5)/2 is prime.
|
|
0
| | |
|
|
|
OFFSET
| 1,1
|
|
|
EXAMPLE
| 9=3^2, 27=3^3, 2187=3^7, 19683=3^9, but 300763=67^3 - is there any rule?
|
|
|
MATHEMATICA
| pp = Join[{1}, Select[ Range[10^7], Apply[GCD, Last[ Transpose[ FactorInteger[ # ]]]] > 1 & ]]; Select[pp, PrimeQ[(# - 5)/2] & ]
|
|
|
CROSSREFS
| Sequence in context: A020254 A124396 A020281 * A053825 A033479 A034116
Adjacent sequences: A075536 A075537 A075538 * A075540 A075541 A075542
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Oct 11 2002
|
|
|
EXTENSIONS
| Extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 14 2002
|
| |
|
|
