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Primes p such that p = a^2 + b^2 for a,b>0 and a+b is prime.
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%I #16 Feb 19 2013 17:54:11

%S 2,5,13,17,29,37,61,73,89,97,101,109,149,157,181,193,229,241,257,269,

%T 277,293,349,409,421,433,461,521,541,593,601,641,661,701,709,733,769,

%U 797,829,853,881,929,937,953,997,1009,1021,1049,1061,1069,1109,1117

%N Primes p such that p = a^2 + b^2 for a,b>0 and a+b is prime.

%C Let q=a+b. For a specific prime q, the number of distinct primes p that are the sum of two squares is A082519(q)/2.

%C Primes p of the form (q-b)^2 + b^2, where q is prime and 0<b<q.

%H T. D. Noe, <a href="/A099332/b099332.txt">Table of n, a(n) for n=1..1000</a>

%F Primes p such that p = (q^2 + x^2)/2, where q is prime and |x| < q. - Thomas Ordowski, Feb 15 2013

%e 29 is in this sequence because 29=2^2+5^2 and 2+5 is prime.

%t Needs["NumberTheory`NumberTheoryFunctions`"]; lst={2}; Do[n=4k+1; If[PrimeQ[n], If[PrimeQ[Plus@@QuadraticRepresentation[1, n]], AppendTo[lst, n]]], {k, 500}]; lst

%Y Cf. A082519 (number of times that k^2 + (n-k)^2 is prime for 1 <= k <= n-1).

%K nonn

%O 1,1

%A _T. D. Noe_, Oct 15 2004