Positive numbers of the form 4*n^2 - 1 which are not semiprimes.

Terms

a(0) =3a(1) =63a(2) =99a(3) =195a(4) =255a(5) =399a(6) =483a(7) =575a(8) =675a(9) =783a(10) =1023a(11) =1155a(12) =1295a(13) =1443a(14) =1599a(15) =1935a(16) =2115a(17) =2303a(18) =2499a(19) =2703a(20) =2915a(21) =3135a(22) =3363a(23) =3843a(24) =4095a(25) =4355a(26) =4623a(27) =4899a(28) =5475a(29) =5775