Twice a square but not the sum of 2 distinct squares.

Terms

a(0) =0a(1) =2a(2) =8a(3) =18a(4) =32a(5) =72a(6) =98a(7) =128a(8) =162a(9) =242a(10) =288a(11) =392a(12) =512a(13) =648a(14) =722a(15) =882a(16) =968a(17) =1058a(18) =1152a(19) =1458a(20) =1568a(21) =1922a(22) =2048a(23) =2178a(24) =2592a(25) =2888a(26) =3528a(27) =3698a(28) =3872a(29) =4232