|
| |
|
|
A139428
|
|
Smallest prime p such that M(n)^2-p*M(n)-1 is prime with M(n)= Mersenne primes =A000668(n).
|
|
7
| |
|
|
5, 7, 5, 17, 43, 67, 41, 53, 311, 317, 317, 43, 1427, 37, 25693, 563, 17239, 911, 11497, 112247, 1259, 190639, 138569, 296713, 27733, 11777
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 2,1
|
|
|
COMMENTS
| All primes certified using openpfgw_v12 from primeform group
|
|
|
EXAMPLE
| 7*7-5*7-1=13 prime 7=M(2)=2^3-1 so k(2)=5
31*31-7*31-1=743 prime 31=M(3)=2^5-1 so k(3)=7
|
|
|
CROSSREFS
| Cf. A000668, A139424, A139425, A139426, A139427, A139429, A139430, A139421.
Sequence in context: A121595 A125294 A177735 * A063005 A145577 A144478
Adjacent sequences: A139425 A139426 A139427 * A139429 A139430 A139431
|
|
|
KEYWORD
| hard,more,nonn
|
|
|
AUTHOR
| Pierre CAMI (pierre-cami(AT)bbox.fr), Apr 21 2008
|
| |
|
|
