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A279423
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Numbers k such that k^2 has an odd number of digits and the middle digit is 3.
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3
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111, 124, 128, 139, 146, 156, 177, 188, 213, 231, 269, 287, 312, 1036, 1041, 1055, 1060, 1074, 1088, 1097, 1106, 1115, 1124, 1133, 1146, 1159, 1172, 1189, 1193, 1214, 1218, 1222, 1226, 1274, 1278, 1282, 1286, 1305, 1309, 1313, 1328, 1343, 1354, 1365, 1376
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OFFSET
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1,1
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LINKS
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EXAMPLE
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111^2 = 12(3)21, 231^2 = 53(3)61, 1214^2 = 147(3)796.
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MATHEMATICA
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ond3Q[n_]:=Module[{idn2=IntegerDigits[n^2], len}, len=Length[idn2]; OddQ[ len] && idn2[[(len+1)/2]]==3]; Select[Range[1400], ond3Q] (* Harvey P. Dale, Apr 06 2018 *)
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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