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A248019
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Values of x in equation A142508(n)=x^2+13y^2.
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2
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1, 12, 14, 14, 25, 27, 25, 14, 1, 40, 1, 27, 38, 40, 12, 14, 1, 53, 14, 1, 51, 40, 27, 64, 64, 14, 66, 64, 77, 77, 79, 66, 79, 77, 25, 38, 77, 40, 1, 79, 64, 53, 12, 92, 90, 51, 66, 77, 25, 64, 92, 77, 1, 79, 64, 53, 1, 103, 38, 12, 14, 53, 1, 77, 116, 79, 116, 92, 118, 118, 77, 103, 66, 118, 38
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(1)=1 because A142508(1)=53=1^2+13*2^2 (x=1,y=2);
a(2)=12 because A142508(2)=157=12^2+13*1^2 (x=12, y=1).
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MATHEMATICA
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f[n_] := FindInstance[n == x^2 + 13 y^2 && x > 0 && y > 0, {x, y}, Integers][[1, 1, 2]]; f@# & /@ Select[ Prime@ Range@ 1840, Mod[#, 52] == 1 &] (* Robert G. Wilson v, Oct 06 2014 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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