OFFSET
1,3
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Triangular Number
MAPLE
N:= 1000: # for all terms <= N
S:= {0, 1}:
for i from 2 do
t:= i*(i+1)/2;
if t > N then break fi;
S:= S union select(`<=`, map(`*`, S, t), N)
od:
sort(convert(S, list)); # Robert Israel, Apr 21 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 14 2020
STATUS
approved