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%I #6 May 28 2023 15:01:32
%S 13,19,31,103,108,117,121,125,129,133,140,147,157,160,175,178,194,199,
%T 204,209,216,225,236,238,240,260,262,264,275,284,291,296,301,306,1003,
%U 1008,1013,1018,1023,1028,1047,1052,1066,1080,1094,1103,1112,1121,1130
%N Numbers k such that k^2 has an odd number of digits and the middle digit is 6.
%H Lars Blomberg, <a href="/A279426/b279426.txt">Table of n, a(n) for n = 1..10000</a>
%e 13^2 = 1(6)9, 133^2 = 17(6)89, 284^2 = 80(6)56.
%t Select[Range[1200],OddQ[IntegerLength[#^2]]&&IntegerDigits[#^2][[(IntegerLength[ #^2]+1)/2]] == 6&] (* _Harvey P. Dale_, May 28 2023 *)
%Y Cf. A279420-A279425, A279427-A279429.
%K nonn,base,easy
%O 1,1
%A _Lars Blomberg_, Dec 22 2016
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