a(n+1) is the smallest square > a(n) such that every concatenation (n > 1) is a prime.

Terms

a(0) =1a(1) =9a(2) =49a(3) =81a(4) =441a(5) =729a(6) =15129a(7) =33489a(8) =35721a(9) =127449a(10) =184041a(11) =288369a(12) =505521a(13) =594441a(14) =1046529a(15) =4004001a(16) =4941729a(17) =8415801a(18) =14130081a(19) =19474569a(20) =20820969a(21) =21427641a(22) =25070049a(23) =31236921a(24) =33419961a(25) =37197801a(26) =57471561a(27) =58201641a(28) =58844241