A279422 Numbers k such that k^2 has an odd number of digits and the middle digit is 2.

11, 15, 18, 23, 25, 27, 101, 106, 115, 135, 149, 159, 162, 165, 168, 171, 174, 185, 193, 198, 203, 208, 215, 222, 233, 235, 265, 267, 278, 285, 292, 297, 302, 307, 315, 1001, 1006, 1011, 1016, 1021, 1026, 1031, 1045, 1050, 1064, 1069, 1078, 1083, 1092, 1101

Offset: 1

Author

Lars Blomberg, Dec 22 2016

Keywords

• nonn
• base
• easy

Examples

			11^2 = 1(2)1, 135^2 = 18(2)25, 285^2 = 81(2)25.
		

Links

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

Crossrefs

Cf. A279420-A279421, A279423-A279429.

Programs

Mathematica

Select[Range[1101], OddQ[len=Length[IntegerDigits[#^2]]]&&Part[IntegerDigits[#^2], (len+1)/2]==2 &] (* Stefano Spezia, Oct 03 2023 *)