

A180269


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


3



2, 7, 37, 36472996377170786527, 2954312706550833698779, 3990838394187339929534246675572349035477, 2120895147045314119491609587512844743630072393, 228532044137599177017869183161846685251274404207185590172004697234871412029099114059347
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Terms a(9) through a(12) have, respectively, 93, 94, 149, and 156 digits.  Harvey P. Dale, May 11 2013


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..15


MATHEMATICA

Select[Table[3^n+3n+1, {n, 0, 100}], PrimeQ] (* Harvey P. Dale, May 11 2013 *)


PROG

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


CROSSREFS

Cf. A176805, A171058.
Sequence in context: A196916 A182331 A173762 * A036432 A275621 A094431
Adjacent sequences: A180266 A180267 A180268 * A180270 A180271 A180272


KEYWORD

hard,nonn


AUTHOR

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


EXTENSIONS

a(8) from Harvey P. Dale, May 11 2013


STATUS

approved



