A279424 Numbers k such that k^2 has an odd number of digits and the middle digit is 4.

2, 12, 21, 29, 102, 107, 116, 120, 132, 136, 143, 153, 180, 183, 191, 196, 201, 206, 220, 229, 271, 280, 294, 299, 304, 309, 1002, 1007, 1012, 1017, 1022, 1027, 1046, 1051, 1065, 1070, 1079, 1093, 1102, 1111, 1120, 1129, 1142, 1151, 1155, 1164, 1168, 1181

Offset

1,1

Links

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

Example

2^2 = (4), 136^2 = 18(4)96, 1017^2 = 103(4)289.

Mathematica

Select[Range[1200], OddQ[IntegerLength[#^2]]&&IntegerDigits[#^2][[(IntegerLength[ #^2]+1)/2]]==4&] (* Harvey P. Dale, Jun 05 2017 *)

Crossrefs

Cf. A279420-A279423, A279425-A279429.

Sequence in context: A034049 A271361 A304813 * A073041 A284595 A053898

Adjacent sequences: A279421 A279422 A279423 * A279425 A279426 A279427

Keyword

nonn,base,easy

Author

Lars Blomberg, Dec 22 2016

Status

approved