A216509 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A216509

Primes which cannot be written in the form a^2 + 6*b^2.

%I #7 Sep 10 2012 12:48:46

%S 2,3,5,11,13,17,19,23,29,37,41,43,47,53,59,61,67,71,83,89,101,107,109,

%T 113,131,137,139,149,157,163,167,173,179,181,191,197,211,227,229,233,

%U 239,251,257,263,269,277,281,283,293,307,311,317,331,347,349,353

%N Primes which cannot be written in the form a^2 + 6*b^2.

%C These are primes congruent to {5, 11, 13, 17, 19, 23} mod 24.

%Y Cf. A033199.

%K nonn

%O 1,1

%A _V. Raman_, Sep 08 2012