Numbers k such that k and k^2 use only the digits 3, 4, 5, 6 and 7.

Terms

a(0) =6a(1) =66a(2) =74a(3) =76a(4) =666a(5) =744a(6) =6666a(7) =6734a(8) =6756a(9) =7574a(10) =57756a(11) =66666a(12) =66756a(13) =67434a(14) =67656a(15) =74474a(16) =74476a(17) =577734a(18) =666666a(19) =666756a(20) =667334a(21) =667566a(22) =667656a(23) =745356a(24) =745476a(25) =6666666a(26) =6666756a(27) =6667566a(28) =6667656a(29) =6674334