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 A069117 #6 Mar 30 2012 18:38:56 %S A069117 1,2,3,4,5,9,10,11,12,13,14,15,16,17,21,22,23,27,28,29,30,31,32,63,64, %T A069117 65,88,89,90,91,92,93,94,95,96,97,98,99,105,106,107,108,109,136,137, %U A069117 138,139,140,141,142,143,144,145,146,147,189,190,191,192,193,194,195 %N A069117 Numbers n such that A068589(n) is a perfect square. %o A069117 (PARI) precision 1000 digits : for(n=1,300,if(sqrt(denominator(sum(i=1,n,1/i^3))/denominator(sum(i=1,n,1/i))) == floor(sqrt(denominator(sum(i=1,n,1/i^3))/denominator(sum(i=1,n,1/i)))),print1(n,","))) %K A069117 easy,nonn %O A069117 1,2 %A A069117 _Benoit Cloitre_, Apr 07 2002