Numbers k such that (k^2 + 4)/2 is a square.

Terms

a(0) =2a(1) =14a(2) =82a(3) =478a(4) =2786a(5) =16238a(6) =94642a(7) =551614a(8) =3215042a(9) =18738638a(10) =109216786a(11) =636562078a(12) =3710155682a(13) =21624372014a(14) =126036076402a(15) =734592086398