A180269 - OEIS

%I #7 May 11 2013 11:16:05

%S 2,7,37,36472996377170786527,2954312706550833698779,

%T 3990838394187339929534246675572349035477,

%U 2120895147045314119491609587512844743630072393,228532044137599177017869183161846685251274404207185590172004697234871412029099114059347

%N Primes of the form 3^n+3*n+1.

%C Terms a(9) through a(12) have, respectively, 93, 94, 149, and 156 digits. - _Harvey P. Dale_, May 11 2013

%H Harvey P. Dale, <a href="/A180269/b180269.txt">Table of n, a(n) for n = 1..15</a>

%t Select[Table[3^n+3n+1,{n,0,100}],PrimeQ] (* _Harvey P. Dale_, May 11 2013 *)

%o (PARI) for(i=0,200,x=3^i+3*i+1;if(isprime(x),print1(x", ")))

%Y Cf. A176805, A171058.

%K hard,nonn

%O 1,1

%A Graziano Aglietti (mg5055(AT)mclink.it), Aug 23 2010

%E a(8) from _Harvey P. Dale_, May 11 2013