

A093625


Primes of the form (3^m + 1)/2.


6




OFFSET

1,1


COMMENTS

Primes can only occur for m=2^k. The next term (if it exists) has k >= 21 (i.e., more than 10^6 decimal digits).  Don Reble, Apr 28 2004. [For the latest results about the search, see A171381.  N. J. A. Sloane, Jun 14 2010]


LINKS

Table of n, a(n) for n=1..6.


EXAMPLE

a(3)=41 because it can be written as (3^4 + 1)/2 = 82/2.


CROSSREFS

A171381 is the main entry for this sequence. Cf. also A059917, A138083.
Sequence in context: A076725 A059917 A255963 * A042447 A176266 A075872
Adjacent sequences: A093622 A093623 A093624 * A093626 A093627 A093628


KEYWORD

nonn,hard


AUTHOR

Hugo Pfoertner, Apr 19 2004


EXTENSIONS

Erroneous terms deleted by N. J. A. Sloane, Jun 14 2010


STATUS

approved



