|
%I #9 Jan 02 2023 12:30:53
%S 0,1,2,3,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,
%T 30,31,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,
%U 115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131
%N Numbers whose squares have an odd number of digits.
%C The sequence of squares starts: 0, 1, 4, 9, 100, 121, 144, 169, 196, 225, 256, ...
%H Lars Blomberg, <a href="/A288657/b288657.txt">Table of n, a(n) for n = 1..10000</a>
%H Jeremy Gardiner, <a href="http://list.seqfan.eu/oldermail/seqfan/2016-December/017135.html">Middle digit in square numbers</a>, Seqfan Mailing list, Dec 12 2016.
%t Join[{0},Select[Range[150],OddQ[IntegerLength[#^2]]&]] (* _Harvey P. Dale_, Apr 07 2018 *)
%Y Cf. A288658, A288659, A288660.
%K nonn,base,easy
%O 1,3
%A _Lars Blomberg_, Jun 13 2017
|
