login
Primes of the form 1 + A094125(k) = 1 + 3*2^k + 2*3^k.
2

%I #25 Aug 18 2024 04:21:00

%S 13,31,79,211,4759,40903,121171,360439,1075171,2326095799,62774702131,

%T 564909404611,53177629140127471641559,

%U 1668770336663931954974790774345703

%N Primes of the form 1 + A094125(k) = 1 + 3*2^k + 2*3^k.

%H Amiram Eldar, <a href="/A095379/b095379.txt">Table of n, a(n) for n = 1..21</a>

%F a(n) = 1 + A094125(A095378(n)). - _Jinyuan Wang_, Aug 26 2019

%e The prime 211 is a term because 211 = 1 + 3*2^4 + 2*3^4.

%t Select[Table[1 + 3*2^k + 2*3^k, {k, 1, 70}], PrimeQ] (* _Amiram Eldar_, Aug 18 2024 *)

%o (PARI) lista(kmax) = {my(p); for(k = 1, kmax, p = 1 + 3*2^k + 2*3^k; if(isprime(p), print1(p, ", ")));} \\ _Amiram Eldar_, Aug 18 2024

%Y Cf. A094125, A095378.

%K nonn

%O 1,1

%A _Labos Elemer_, Jun 07 2004