Untouchable squares.

Terms

a(0) =324a(1) =576a(2) =784a(3) =1296a(4) =2304a(5) =2500a(6) =2704a(7) =3136a(8) =3600a(9) =4356a(10) =5184a(11) =6084a(12) =7056a(13) =8100a(14) =9216a(15) =11236a(16) =11664a(17) =14400a(18) =14884a(19) =15876a(20) =17424a(21) =24336a(22) =24964a(23) =25600a(24) =27556a(25) =28224a(26) =30276a(27) =32400a(28) =33856a(29) =34596