When squared gives number composed just of the digits 1, 2, 3, 4.

Terms

a(0) =1a(1) =2a(2) =11a(3) =12a(4) =18a(5) =21a(6) =38a(7) =111a(8) =182a(9) =338a(10) =462a(11) =482a(12) =1111a(13) =1188a(14) =1488a(15) =1521a(16) =2079a(17) =3338a(18) =3368a(19) =3482a(20) =3512a(21) =3639a(22) =4818a(23) =5868a(24) =10688a(25) =11011a(26) =12018a(27) =17639a(28) =17979a(29) =18012