OFFSET
1,1
COMMENTS
The first number that is the sum in three ways is 2180. The first that is the sum in four ways is 10053736. - Robert Israel, Aug 20 2019
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000 (first 2759 terms from Robert Israel)
FORMULA
A307666(a(n)) > 1.
MAPLE
N:= 10000: # for terms <= N
V:= Vector(N):
for i from 1 while i*(i+1)/2 <= N do
s:= i*(i+1)*(i+2)/6;
for j from i-1 to 0 by -1 do
t:= j*(j+1)*(j+2)/6;
if s-t > N then break fi;
V[s-t]:= V[s-t]+1
od;
od:
select(t -> V[t]>1, [$1..N]); # Robert Israel, Aug 20 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Aug 17 2019
STATUS
approved