Positive integers of the form x^2+3xy-y^2.

Terms

a(0) =1a(1) =3a(2) =4a(3) =9a(4) =12a(5) =13a(6) =16a(7) =17a(8) =23a(9) =25a(10) =27a(11) =29a(12) =36a(13) =39a(14) =43a(15) =48a(16) =49a(17) =51a(18) =52a(19) =53a(20) =61a(21) =64a(22) =68a(23) =69a(24) =75a(25) =79a(26) =81a(27) =87a(28) =92a(29) =100