|
|
A111638
|
|
Numbers having a unique partition into three positive triangular numbers.
|
|
6
|
|
|
3, 5, 7, 8, 9, 10, 13, 14, 15, 16, 18, 24, 25, 36, 38, 50, 53, 55, 60, 69, 81, 83, 99, 110, 119
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
Example: 119=55+36+28
|
|
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, 1, lim}, {b, a, trigInv[trig[lim]-trig[a]]}, {c, b, trigInv[trig[lim]-trig[a]-trig[b]]}]; Flatten[Position[nLst, 1]]
|
|
CROSSREFS
|
Cf. A060773 (n having a unique partition into three nonnegative triangular numbers).
|
|
KEYWORD
|
fini,full,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|