A060773 Numbers having a unique partition into three nonnegative triangular numbers.

0, 1, 2, 4, 5, 8, 11, 14, 20, 29, 50, 53

Offset: 0

Author

Erich Friedman, Apr 24 2001

Keywords

• nonn
• fini
• full

Crossrefs

Cf. A000217, A061262, A053614.

Cf. A111638 (n having a unique partition into three positive triangular numbers).

Programs

Mathematica

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, 0, lim}, {b, a, trigInv[trig[lim]-trig[a]]}, {c, b, trigInv[trig[lim]-trig[a]-trig[b]]}]; Flatten[Position[nLst, 1]] (* T. D. Noe, Aug 10 2005 *)