OFFSET

1,1

MATHEMATICA

r = 144; lst = Table[0, {r}]; lim = Floor[Sqrt[8*r - 7]]; Do[num = (i^2 + i)/2 + (j^2 + j)/2; If[num <= r, lst[[num]]++], {i, lim}, {j, i - 1}]; Flatten@Position[lst, 1]

CROSSREFS

KEYWORD

nonn

AUTHOR

Arkadiusz Wesolowski, Dec 02 2015

STATUS

approved