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 A102646 #12 Nov 11 2019 12:08:08
%S A102646 1,4,9,16,18,25,36,48,49,50,64,75,81,98,100,121,144,147,162,169,180,
%T A102646 192,196,225,242,245,256,289,294,300,320,324,338,361,363,400,405,441,
%U A102646 448,450,484,507,529,567,576,578,588,605,625,648,676,700,720,722,726,729
%N A102646 Numbers of form j k^2 with 1 <= j <= k, gcd(j,k) = 1.
%C A102646 Numbers n such that A102448(n) >= 1.
%C A102646 All positive squares x^2 are in the sequence with j = 1, k = x.
%H A102646 David A. Corneth, <a href="/A102646/b102646.txt">Table of n, a(n) for n = 1..10000</a>
%e A102646 180 is in the sequence with j = 5, k = 6.
%o A102646 (PARI) is(n) = {my(f = factor(n), podd = 1, peven = 1); for(i = 1, #f~, if(bittest(f[i, 2], 0), podd *= f[i, 1]^f[i, 2] , peven *= f[i, 1]^(f[i, 2] >> 1) ) ); podd <= peven } \\ _David A. Corneth_, Nov 11 2019
%Y A102646 Cf. A102448.
%K A102646 nonn
%O A102646 1,2
%A A102646 _Leroy Quet_, Feb 25 2005
%E A102646 Edited by _David W. Wilson_, Sep 03 2005