Primes of special structure

Cyclamen Persicum · 2003-03-10, 10:08

Since Mersenne primes are very rare, I'm interested in
others for which simple criteria exists.
There is a criteria (3^...) for Fermat numbers,
but you know only 5 of them are prime...
Are they?
I've discivered then 3^n+2 is often prime,
for instance,
1
2
3
4
8
10
14
15
24
26
36
63
98
110
123
126
139
235
243
315
363
386
391
494
1131
1220
1503
1858
and so on...

Cyclamen Persicum · 2003-03-19, 17:51

http://perso.wanadoo.fr/yves.gallot/primes/results.html

Exluminis · 2003-03-25, 03:20

3 ~= 2.73... (e)

2003-03-10, 10:08	#1
Cyclamen Persicum Mar 2003 3⁴ Posts	Primes of special structure Since Mersenne primes are very rare, I'm interested in others for which simple criteria exists. There is a criteria (3^...) for Fermat numbers, but you know only 5 of them are prime... Are they? I've discivered then 3^n+2 is often prime, for instance, 1 2 3 4 8 10 14 15 24 26 36 63 98 110 123 126 139 235 243 315 363 386 391 494 1131 1220 1503 1858 and so on...

2003-03-19, 17:51	#2
Cyclamen Persicum Mar 2003 81₁₀ Posts	Generalized Fermat Number http://perso.wanadoo.fr/yves.gallot/primes/results.html

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2003-03-25, 03:20	#3
Exluminis Mar 2003 3² Posts	3 ~= 2.73... (e)