A279425 -id:A279425 - cp's OEIS frontend

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

Lars Blomberg, Dec 22 2016

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

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

Cf. A279420-A279423, A279425-A279429.

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

A279426 Numbers k such that k^2 has an odd number of digits and the middle digit is 6.

Original entry on oeis.org

13, 19, 31, 103, 108, 117, 121, 125, 129, 133, 140, 147, 157, 160, 175, 178, 194, 199, 204, 209, 216, 225, 236, 238, 240, 260, 262, 264, 275, 284, 291, 296, 301, 306, 1003, 1008, 1013, 1018, 1023, 1028, 1047, 1052, 1066, 1080, 1094, 1103, 1112, 1121, 1130

Offset: 1

Lars Blomberg, Dec 22 2016

			13^2 = 1(6)9, 133^2 = 17(6)89, 284^2 = 80(6)56.

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

Cf. A279420-A279425, A279427-A279429.

Select[Range[1200],OddQ[IntegerLength[#^2]]&&IntegerDigits[#^2][[(IntegerLength[ #^2]+1)/2]] == 6&] (* Harvey P. Dale, May 28 2023 *)

cp's OEIS Frontend

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

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