This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A036897 #19 Jul 02 2019 18:06:14
%S A036897 1,3,15,21,25,33,39,45,51,57,69,75,81,87,93,111,123,129,141,159,177,
%T A036897 183,189,201,213,219,225,237,249,267,291,303,309,315,321,327,339,343,
%U A036897 381,393,405,411,417,447,453,471,489,495,501,519,525,537,543,567,573
%N A036897 Square root of odd refactorable numbers.
%C A036897 Odd refactorable numbers are always squares.
%H A036897 Amiram Eldar, <a href="/A036897/b036897.txt">Table of n, a(n) for n = 1..1001</a>
%H A036897 S. Colton, <a href="http://www.cs.uwaterloo.ca/journals/JIS/colton/joisol.html">Refactorable Numbers - A Machine Invention</a>, J. Integer Sequences, Vol. 2, 1999, #2.
%H A036897 S. Colton, <a href="http://web.archive.org/web/20070831060523/http://www.dai.ed.ac.uk/homes/simonco/research/hr/">HR - Automatic Theory Formation in Pure Mathematics</a>
%F A036897 a(n) = sqrt(A036896(n)). - _Amiram Eldar_, Jul 02 2019
%e A036897 15^2 is refactorable because 225 has 9 divisors and 9 divides 225.
%t A036897 Select[Range[1, 1000, 2], Divisible[#^2, DivisorSigma[0,#^2]] &] (* _Amiram Eldar_, Jul 02 2019 *)
%o A036897 (PARI) isrefac(n) = ! (n % numdiv(n));
%o A036897 lista(nn) = {forstep (n = 1, nn, 2, if (isrefac(n), print1(sqrtint(n), ", ")););} \\ _Michel Marcus_, Aug 31 2013
%Y A036897 Cf. A033950, A036896.
%K A036897 nonn
%O A036897 1,2
%A A036897 Simon Colton (simonco(AT)cs.york.ac.uk)