Nonsquares mod 54.

Terms

a(0) =2a(1) =3a(2) =5a(3) =6a(4) =8a(5) =11a(6) =12a(7) =14a(8) =15a(9) =17a(10) =18a(11) =20a(12) =21a(13) =23a(14) =24a(15) =26a(16) =29a(17) =30a(18) =32a(19) =33a(20) =35a(21) =38a(22) =39a(23) =41a(24) =42a(25) =44a(26) =45a(27) =47a(28) =48a(29) =50