OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
M:= 4000: # for terms <= M
V:= Vector(M):
for a from 1 while 4*a^3 < M do
for b from a+1 while a^3 + 3*b^3 < M do
for c from b+1 while a^3 + b^3 + 2*c^3 < M do
for d from c+1 do
v:= a^3 + b^3 + c^3 + d^3;
if v > M then break fi;
V[v]:= V[v]+1
od od od od:
select(t -> V[t] > 1, [$1..M]); # Robert Israel, Oct 23 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved