Numbers k such that k and k^2 use only the digits 2, 3, 6, 7 and 8.

Terms

a(0) =6a(1) =26a(2) =826a(3) =876a(4) =8876a(5) =28876a(6) =873626a(7) =2763626a(8) =8736626a(9) =28866376a(10) =28873626a(11) =82363626a(12) =88788326a(13) =276366376a(14) =823277826a(15) =873366376a(16) =7888386326a(17) =8286366326a(18) =27888866376a(19) =28868267826a(20) =62238788326a(21) =62267678826a(22) =277266773826a(23) =278723273826a(24) =288663683876a(25) =823636672826a(26) =823873366376a(27) =887878833326a(28) =887883622826