OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
Wikipedia, Integer Triangle
MAPLE
N:= 1000: # to get all terms <= N
S:= {}:
for a from 1 to floor(sqrt(N/3)) do
for b from a to floor(sqrt((N-a^2)/2)) do
S:= S union map(c -> a^2 + b^2 + c^2, {$b .. floor(sqrt(min(a^2+b^2-1, N-a^2-b^2)))})
od od:
sort(convert(S, list)); # Robert Israel, Jan 01 2020
MATHEMATICA
Flatten[Table[If[Sum[Sum[(Floor[Sqrt[i]] - Floor[Sqrt[i - 1]]) (Floor[Sqrt[k]] - Floor[Sqrt[k - 1]]) (Floor[Sqrt[n - k - i]] - Floor[Sqrt[n - k - i - 1]])*Sign[Floor[(i + k)/(n - i - k + 1)]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}] > 0, n, {}], {n, 200}]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Jul 28 2019
STATUS
approved