Numbers k such that k and k^2 use only the digits 2, 6, 7, 8 and 9.

Terms

a(0) =26a(1) =27a(2) =277a(3) =826a(4) =887a(5) =2826a(6) =8826a(7) =8887a(8) =9286a(9) =27886a(10) =29626a(11) =29777a(12) =79286a(13) =88277a(14) =269777a(15) =277267a(16) =286827a(17) =298826a(18) =299827a(19) =792267a(20) =828667a(21) =829626a(22) =989277a(23) =989286a(24) =989887a(25) =2772667a(26) =2772886a(27) =2792667a(28) =2877886a(29) =2962767