A279425 Numbers k such that k^2 has an odd number of digits and the middle digit is 5.

16, 112, 150, 163, 166, 169, 172, 186, 211, 218, 227, 242, 244, 246, 248, 250, 252, 254, 256, 258, 273, 282, 289, 314, 1032, 1037, 1042, 1056, 1061, 1075, 1084, 1089, 1098, 1107, 1116, 1125, 1134, 1138, 1147, 1160, 1173, 1177, 1194, 1198, 1219, 1223, 1227

Offset

1,1

Links

Lars Blomberg, Table of n, a(n) for n = 1..10000

Example

16^2 = 2(5)6, 218^2 = 47(5)24, 1075^2 = 115(5)625.

Mathematica

Select[Range[1227], OddQ[len=Length[IntegerDigits[#^2]]]&&Part[IntegerDigits[#^2], (len+1)/2]==5 &] (* Stefano Spezia, Oct 03 2023 *)

Crossrefs

Cf. A279420-A279424, A279426-A279429.

Sequence in context: A240786 A213754 A371114 * A144449 A035016 A000143

Adjacent sequences: A279422 A279423 A279424 * A279426 A279427 A279428

Keyword

nonn,base,easy

Author

Lars Blomberg, Dec 22 2016

Status

approved