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A106861
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Primes of the form x^2+xy+4y^2, with x and y nonnegative.
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2
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19, 31, 79, 109, 151, 181, 199, 211, 229, 271, 331, 349, 409, 421, 439, 499, 571, 601, 619, 631, 661, 691, 709, 769, 811, 829, 859, 919, 991, 1021, 1039, 1051, 1069, 1129, 1171, 1201, 1249, 1291, 1321, 1381, 1399, 1429, 1459, 1471, 1489, 1531, 1579
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OFFSET
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1,1
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COMMENTS
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Discriminant=-15.
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LINKS
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MAPLE
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N:= 1000; # to get all terms <= N
Primes:= select(isprime, [seq(2*n+1, n=1..floor((N-1)/2))]):
filter:= proc(p) local S;
S:= remove(hastype, [isolve(x^2+x*y+4*y^2=p)], negint);
nops(S) > 0
end proc:
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MATHEMATICA
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QuadPrimes2[1, 1, 4, 1000000] (* see A106856 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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