Here's a good one: 12395067022025302245408215823361, 104 bits.
(from which you can see that not all prime exponents containing the "number of the best" will generate prime mersennes :razz:)

[QUOTE=LaurV;331033]Here's a good one: 12395067022025302245408215823361, 104 bits.
(from which you can see that not all prime exponents containing the [STRIKE]"number of the best"[/STRIKE] will generate prime mersennes :razz:)[/QUOTE]
"number of the BEAST"

[QUOTE=c10ck3r;331038]"number of the BEAST"[/QUOTE]
grrr, typo, thanks

M95516249819281897377329792747204747051937323318703014161875271870743369159415765467622402105668679795781959994061775011707821819120345026036123142898041417744024085438782757861002649408975294945304266551957165557916259132607823871 has a factor: 191032499638563794754659585494409494103874646637406028323750543741486738318831530935244804211337359591563919988123550023415643638240690052072246285796082835488048170877565515722005298817950589890608533103914331115832518265215647743

[QUOTE=jnml;331225]M95516249819281897377329792747204747051937323318703014161875271870
7433691594157654676224021056686797957819599940617750117078218191203450260361231428980
41417744024085438782757861002649408975294945304266551957165557916259132607823871 has a factor: 191032499638563794754659585494409494103874646637406028323750543741486738318831530935244
804211337359591563919988123550023415643638240690052072246285796082835488048170877565515
722005298817950589890608533103914331115832518265215647743[/QUOTE]

I'm just curious. How did you get these two numbers? And what's special of the exponent?

[QUOTE=dabaichi;331245]I'm just curious. How did you get these two numbers? And what's special of the exponent?[/QUOTE]

Nothing special above the fact that both the factor and the exponent are PRPs. Otherwise it's a 2p+1 | Mp (i.e. k == 1), so I actually cheated (in a sense).

Got that from a toy program of mine, it's just the size surprised me a bit ;-)

[CODE]
(16:38) jnml@fsc-r550:~/src/tmp/mersenne/ff$ time ./ff
2: 23 | M11 (5 bits)
2: 47 | M23 (6 bits)
2: 383 | M191 (9 bits)
14: 479 | M239 (9 bits)
20: 167 | M83 (8 bits)
26: 863 | M431 (10 bits)
26: 7421703487487 | M3710851743743 (43 bits)
26: 143556623544770914273611162510277214207 | M71778311772385457136805581255138607103 (127 bits)
32: 263 | M131 (9 bits)
32: 290271069732863 | M145135534866431 (49 bits)
44: 359 | M179 (9 bits)
44: 719 | M359 (10 bits)
44: 1439 | M719 (11 bits)
44: 2879 | M1439 (12 bits)
44: 23039 | M11519 (15 bits)
44: 1474559 | M737279 (21 bits)
44: 2949119 | M1474559 (22 bits)
44: 24159191039 | M12079595519 (35 bits)
44: 6184752906239 | M3092376453119 (43 bits)
50: 52223 | M26111 (16 bits)
56: 1823 | M911 (11 bits)
56: 3825205247 | M1912602623 (32 bits)
62: 503 | M251 (9 bits)
62: 191032499638563794754659585494409494103874646637406028323750543741486738318831530935244804211337359591563919988123550023415643638240690052072246285796082835488048170877565515722005298817950589890608533103914331115832518265215647743 | M95516249819281897377329792747204747051937323318703014161875271870743369159415765467622402105668679795781959994061775011707821819120345026036123142898041417744024085438782757861002649408975294945304266551957165557916259132607823871 (765 bits)
^C
real 0m31.379s
user 0m31.070s
sys 0m0.080s
(16:38) jnml@fsc-r550:~/src/tmp/mersenne/ff$
[/CODE]

EDIT: The code is now available [URL="https://github.com/cznic/mathutil/blob/master/ff/main.go"]here[/URL].

factor5 confirm the factor found.

[QUOTE=firejuggler;331273]factor5 confirm the factor found.[/QUOTE]
Thanks for the confirmation. Are such "factors" worth of reporting here? For example:

[CODE]
jnml@fsc-r630:~/src/github.com/cznic/mathutil/ff$ time ./ff -c 1382 -d 10s
1382: 23202889727 | M11601444863 (35 bits)
1382: 2891317468805925583122310289685036337676269648223968521576930801170224130471293604830368928083599358133453548705464010629846117567184743543864401985621482209720123399448999256896093377478118494454636064824009640486909425185943889123952719307865058813784823875371947571635800099775698380593420250938639525924694459005059051692445445662364099847064237399153239430674586254346911706508030497459384755111708766149920027758576898244058419917181406937087 | M1445658734402962791561155144842518168838134824111984260788465400585112065235646802415184464041799679066726774352732005314923058783592371771932200992810741104860061699724499628448046688739059247227318032412004820243454712592971944561976359653932529406892411937685973785817900049887849190296710125469319762962347229502529525846222722831182049923532118699576619715337293127173455853254015248729692377555854383074960013879288449122029209958590703468543 (1487 bits)
^C
real 0m6.973s
user 0m6.816s
sys 0m0.060s
jnml@fsc-r630:~/src/github.com/cznic/mathutil/ff$
[/CODE]

I'm afraid that the range considered usefull are only the M below 100 millions and the range
between 332.2 -334 millions. Outside of these range, it is not really usefull (outside of personnal quest).

[QUOTE=jnml;331251]Nothing special above the fact that both the factor and the exponent are PRPs. Otherwise it's a 2p+1 | Mp (i.e. k == 1), so I actually cheated (in a sense). ...
[/QUOTE]

Thanks for your explanations!

59933213 haz dat factor of teh 266130256367911424981339321 87.78 bitz.:ignore: