A248019 Values of x in equation A142508(n)=x^2+13y^2.

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

Offset

1,2

Links

Table of n, a(n) for n=1..75.

Example

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).

Mathematica

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 *)

Crossrefs

Cf. A033210, A142508, A248221, A248019(values of y).

Sequence in context: A121288 A075477 A075482 * A275113 A043651 A043701

Adjacent sequences: A248016 A248017 A248018 * A248020 A248021 A248022

Keyword

nonn

Author

Zak Seidov, Oct 06 2014

Status

approved