|
| |
|
|
A098041
|
|
Arithmetic mean of successive Mersenne primes.
|
|
0
| |
|
|
5, 19, 79, 4159, 69631, 327679, 1074003967, 1152921505680588799, 309485010974266573331628031, 81129947899616503040857729925119, 85070672859873030472525347646947196927
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Sequence is based on the following (false) conjecture Shanks mentions in his paper (p.6), which someone else made: "If M_p1 and M_p2 are successive Mersenne primes, their arithmetic mean is also prime." The first four values in the sequence are prime, while the rest up to (2^756839-1 + 2^216091-1)/2 are not. Conjecture: there are no more primes in this sequence after 4159.
|
|
|
LINKS
| D. Shanks, Squfof Notes
|
|
|
EXAMPLE
| a(3)=79 because (31+127)/2 = 79.
|
|
|
CROSSREFS
| Cf. A000043.
Sequence in context: A125657 A111929 A146030 * A149780 A149781 A149782
Adjacent sequences: A098038 A098039 A098040 * A098042 A098043 A098044
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Oct 24 2004
|
| |
|
|
