Even numbers x such that x^2 + y^2 = 13^n with x and y coprime.

Terms

a(0) =0a(1) =2a(2) =12a(3) =46a(4) =120a(5) =122a(6) =828a(7) =6554a(8) =28560a(9) =86158a(10) =145668a(11) =246046a(12) =3369960a(13) =17021162a(14) =58317492a(15) =128629846a(16) =13651680a(17) =1590277918a(18) =9719139348a(19) =37641223154a(20) =99498527400a(21) =107655263398a(22) =647549275812