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%I #10 May 17 2018 16:25:17
%S 1,2,11,16,19,29,55,83,143,163,245,262,421,451,487,731,889,1331,1342,
%T 1459,1487,2189,2242,2323,2537,2573,2644,2662,3788,4375,4562,6563,
%U 6688,6967,7036,7082,7696,8035
%N Numbers n not divisible by 3 such that n^2 written in base 3 has no digit > 1.
%C The first condition is added to avoid trivial solutions of the form a(k)*3^m, whose square, written in base 3, would just have 0's appended w.r.t. a(k)^2, and thus always have the digits 1 and 0.
%C An infinite subset of solutions is given by { 3^m+2; m>1 } U { 2*3^m+1; m>1 }.
%H Harvey P. Dale, <a href="/A257283/b257283.txt">Table of n, a(n) for n = 1..200</a>
%t Select[Range[10000],Mod[#,3]!=0&&Max[IntegerDigits[#^2,3]]<2&] (* _Harvey P. Dale_, May 17 2018 *)
%o (PARI) b=3;for(n=1,9999,n%b||next;vecmax(digits(n^2,b))>1||print1(n","))
%Y Cf. A257284, A230030.
%K nonn,base
%O 1,2
%A _M. F. Hasler_, May 02 2015
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