A060773 - OEIS

A060773

Numbers having a unique partition into three nonnegative triangular numbers.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..11.

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)

CROSSREFS

Cf. A000217, A061262, A053614.

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

Sequence in context: A191122 A191338 A307518 * A330440 A222044 A288937

Adjacent sequences: A060770 A060771 A060772 * A060774 A060775 A060776

KEYWORD

nonn,fini,full

AUTHOR

Erich Friedman, Apr 24 2001

STATUS

approved