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 A066851 #6 May 10 2013 12:44:57 %S A066851 0,0,1,0,3,0,3,3,3,0,9,1,3,6,6,3,9,0,9,9,6,0,15,6,3,12,10,3,15,0,15, %T A066851 12,6,6,18,9,3,12,18,6,21,0,9,21,9,6,27,7,9,12,18,9,15,12,18,24,6,0, %U A066851 33,6,15,18,21,12,18,12,9,27,18,0,39,9,9,24,19,21,18,0,27,27,18,6,33,18,6 %N A066851 Number of ordered solutions (x,y,z) to xy + yz + zx = n with x,y,z >= 1. %H A066851 T. D. Noe, <a href="/A066851/b066851.txt">Table of n, a(n) for n=1..1000</a> %e A066851 a(5) = 3 since there are solutions (2,1,1), (1,2,1), (1,1,2). %Y A066851 a(A025052(n))=0. Cf. A066958. %K A066851 easy,nonn %O A066851 1,5 %A A066851 Colin Mallows, Jan 24 2002 %E A066851 More terms from _Vladeta Jovovic_, Jan 25 2002