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A288657
Numbers whose squares have an odd number of digits.
4
0, 1, 2, 3, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131
OFFSET
1,3
COMMENTS
The sequence of squares starts: 0, 1, 4, 9, 100, 121, 144, 169, 196, 225, 256, ...
LINKS
Jeremy Gardiner, Middle digit in square numbers, Seqfan Mailing list, Dec 12 2016.
MATHEMATICA
Join[{0}, Select[Range[150], OddQ[IntegerLength[#^2]]&]] (* Harvey P. Dale, Apr 07 2018 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Lars Blomberg, Jun 13 2017
STATUS
approved