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 A111638 #5 Jul 20 2012 21:28:29 %S A111638 3,5,7,8,9,10,13,14,15,16,18,24,25,36,38,50,53,55,60,69,81,83,99,110, %T A111638 119 %N A111638 Numbers having a unique partition into three positive triangular numbers. %C A111638 A063993(a(n)) = 1. - _Reinhard Zumkeller_, Jul 20 2012 %e A111638 Example: 119=55+36+28 %t A111638 trig[n_]:=n(n+1)/2; trigInv[x_]:=Ceiling[Sqrt[Max[0, 2x]]]; lim=100; nLst=Table[0, {trig[lim]}]; Do[n=trig[a]+trig[b]+trig[c]; If[n>0 && n<=trig[lim], nLst[[n]]++ ], {a, 1, lim}, {b, a, trigInv[trig[lim]-trig[a]]}, {c, b, trigInv[trig[lim]-trig[a]-trig[b]]}]; Flatten[Position[nLst, 1]] %Y A111638 Cf. A060773 (n having a unique partition into three nonnegative triangular numbers). %Y A111638 Cf. A002097, A064825. %K A111638 fini,full,nonn %O A111638 1,1 %A A111638 _T. D. Noe_, Aug 10 2005