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 A067751 #12 Aug 09 2025 07:34:42
%S A067751 3,6,7,9,9,12,9,15,12,12,15,19,9,18,18,18,15,18,15,27,18,12,21,30,12,
%T A067751 24,22,21,21,24,21,30,18,18,30,36,9,24,30,30,27,24,15,39,27,18,33,37,
%U A067751 18,30,30,27,21,36,30,48,18,12,39,42,21,30,39,33,30,36,15,45,30,24,45,45,15
%N A067751 Number of solutions in nonnegative integers of x*y+x*z+y*z = n.
%C A067751 An upper bound on the number of solutions appears to be 9*sqrt(n). - _T. D. Noe_, Jun 14 2006
%H A067751 T. D. Noe, <a href="/A067751/b067751.txt">Table of n, a(n) for n = 1..10000</a>
%e A067751 a(3)=7 because of (0,1,3),(0,3,1),(1,0,3),(1,3,0),(3,0,1),(3,1,0),(1,1,1).
%t A067751 CntFunc[s_List] := Module[{len=Length[Union[s]]}, If[len==3,6,If[len==2,3,1]]]; Table[cnt=0; Do[z=(n-x*y)/(x+y); If[IntegerQ[z], cnt=cnt+CntFunc[{x,y,z}]], {x,0,Sqrt[n/3]}, {y, Max[1,x],Sqrt[x^2+n]-x}]; cnt, {n,100}] (* _T. D. Noe_, Jun 14 2006 *)
%Y A067751 Cf. A067752, A067753, A067754.
%K A067751 easy,nonn
%O A067751 1,1
%A A067751 _Colin Mallows_, Jan 31 2002
%E A067751 Corrected and extended by _T. D. Noe_, Jun 14 2006