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Primes of the form 384*n + 257.
4

%I #12 Sep 08 2022 08:46:06

%S 257,641,1409,3329,4481,7937,9473,9857,11393,11777,12161,13313,13697,

%T 14081,15233,16001,17921,19073,19457,19841,21377,23297,25601,28289,

%U 30593,30977,35201,35969,36353,37889,38273,39041,40193,40577,40961,41729,43649,44417

%N Primes of the form 384*n + 257.

%C Every Fermat number greater than 257 has a prime factor of the form 384*n + 257, n > 0.

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Fermat_number">Fermat number</a>

%t Select[Table[384*n + 257, {n, 0, 115}], PrimeQ]

%o (Magma) [384*n+257 : n in [0..115] | IsPrime(384*n+257)]

%Y Subsequence of A107181 (primes of the form 8x^2+9y^2).

%Y Cf. A000215, A023394, A094358, A229853, A229855, A229856.

%K nonn

%O 1,1

%A _Arkadiusz Wesolowski_, Oct 01 2013