Numbers k such that k and k^2 use only the digits 2, 3, 6, 7 and 9.

Terms

a(0) =3a(1) =6a(2) =26a(3) =27a(4) =63a(5) =277a(6) =963a(7) =7923a(8) =27923a(9) =62637a(10) =79327a(11) =263937a(12) =269777a(13) =626637a(14) =962637a(15) =962963a(16) =969223a(17) =996363a(18) =2639937a(19) =2696923a(20) =2696973a(21) =2779736a(22) =7932637a(23) =9996363a(24) =9996963a(25) =26396363a(26) =27639236a(27) =62633676a(28) =79326376a(29) =79332637