Numbers k such that k and k^2 use only the digits 2, 4, 6, 7 and 9.

Terms

a(0) =2a(1) =7a(2) =26a(3) =27a(4) =264a(5) =277a(6) =474a(7) =792a(8) =964a(9) =4762a(10) =6926a(11) =22277a(12) =26962a(13) =27924a(14) =49262a(15) =49426a(16) =49474a(17) =49777a(18) =69262a(19) =264474a(20) =269777a(21) =474262a(22) =476962a(23) =494262a(24) =494462a(25) =494464a(26) =497262a(27) =497662a(28) =499474a(29) =692262