Positive numbers of the form -x^4+6x^2 y^2-y^4 (where x,y are integers).

Terms

a(0) =4a(1) =7a(2) =64a(3) =112a(4) =119a(5) =164a(6) =239a(7) =324a(8) =527a(9) =567a(10) =644a(11) =959a(12) =1024a(13) =1519a(14) =1792a(15) =1904a(16) =2047a(17) =2500a(18) =2624a(19) =2884a(20) =3479a(21) =3824a(22) =4207a(23) =4324a(24) =4375a(25) =4879a(26) =4964a(27) =5184a(28) =5572a(29) =6647