Numbers k such that k and k^2 use only the digits 1, 3, 4, 7 and 8.

Terms

a(0) =1a(1) =38a(2) =88a(3) =1188a(4) =4141a(5) =8878a(6) =11478a(7) =18471a(8) =33878a(9) =183878a(10) =844878a(11) =887771a(12) =1347141a(13) =3381378a(14) =33883878a(15) =43344878a(16) =88811471a(17) =177317438a(18) =178374141a(19) =333374141a(20) =338841141a(21) =344743878a(22) =844877141a(23) =887377438a(24) =3334348188a(25) =3441183188a(26) =8817473471a(27) =11483831378a(28) =13347183878a(29) =13371137378