login
A084125
Numbers n such that 13*3^n + 2 is prime.
0
1, 3, 6, 7, 11, 29, 106, 111, 138, 966, 1203, 2719, 3357, 11445, 15066, 16837, 36750
OFFSET
1,2
COMMENTS
Values corresponding to 29, 106, 111, 138, 966, 1203 and 2719 (1299 digits) have been certified prime with Primo. 13*3^3357 + 2 is a probable prime. There are no other terms <= 6000.
No more terms below 50000. - Amiram Eldar, Sep 11 2019
EXAMPLE
Primes 41,353,9479,28433 are 13*3^1+2, 13*3^3+2, 13*3^6+2, 13*3^7+2.
MATHEMATICA
Select[Range[1000], PrimeQ[13 * 3^# + 2] &] (* Amiram Eldar, Sep 11 2019 *)
PROG
(PARI) for(n=1, 6000, if(isprime(13*3^n+2), print1(n, ", ")))
CROSSREFS
Sequence in context: A015819 A298794 A181683 * A053478 A269363 A138037
KEYWORD
nonn,more
AUTHOR
Rick L. Shepherd, May 21 2003
EXTENSIONS
11445 (a pseudoprime) from Huseyin Azoguz (huseyin(AT)mmnetz.de), Nov 30 2008
a(15)-a(17) from Amiram Eldar, Sep 11 2019
STATUS
approved