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%I #14 Sep 02 2018 12:34:35
%S 3001,4001,7001,9001,13001,16001,19001,21001,24001,28001,51001,54001,
%T 55001,61001,69001,70001,76001,81001,88001,90001,93001,96001,97001,
%U 102001,103001,109001,114001,115001,121001,123001,124001,126001,129001
%N Primes of the form 1000*k + 1.
%C Let d be any divisors of 1000, then d and -d are quadratic residues modulo these primes. All terms are of the form x^2 - d*y^2 for d = -40, -25, -10, -8, -5, -4, -2, -1, 2, 5, 8, 10. Conjecture: they are also of the form x^2 - d*y^2 for d = 20, 40, 50, 200. - _Jianing Song_, Aug 29 2018
%o (PARI) for(k=0, 130, if(isprime(1000*k+1), print1(1000*k+1, ", "))) \\ _Jianing Song_, Aug 29 2018
%Y Cf. A064962.
%K nonn
%O 1,1
%A Avik Roy (avik_3.1416(AT)yahoo.co.in), Feb 12 2009
%E More terms from _R. J. Mathar_, Feb 19 2009