|
| |
|
|
A123214
|
|
Primes q such that (2^p + 1)/3 is prime, where p = Prime[q]; or primes in A123176[n].
|
|
1
| |
|
|
2, 3, 5, 7, 11, 31, 43, 1697, 12923, 13103, 77509
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| A123176[n] are the numbers n such that (2^p + 1)/3 is prime, where p = Prime[n]. A123176[n] = PrimePi[A000978[n]]. PrimePi[a(n)] = {1,2,3,4,5,11,14,265,1540,1559,...}.
|
|
|
EXAMPLE
| A123176[n] begin {2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 18, 22, 26, 31, 39, 43, ...}.
Thus
a(1) = 2, a(2) = 3, a(3) = 5, a(4) = 7, a(5) = 11, a(6) = 31, a(7) = 43.
|
|
|
CROSSREFS
| Cf. A123176, A000978, A000979, A001045, A049883, A107036.
Sequence in context: A155833 A028867 A104154 * A119834 A095180 A101989
Adjacent sequences: A123211 A123212 A123213 * A123215 A123216 A123217
|
|
|
KEYWORD
| hard,more,nonn
|
|
|
AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Oct 05 2006
|
|
|
EXTENSIONS
| One more term from Max Alekseyev (maxale(AT)gmail.com), Feb 06 2010
|
| |
|
|
