OFFSET
1,1
COMMENTS
This list contains A117642 (if n=3*k^3, then n^2 = 9*k^6 = 8*k^6 + k^6 = (2*k^2)^3 + (k^2)^3). (Old comment rewritten as suggested by Michel Marcus, Dec 10 2014.)
LINKS
Daniel Arribas, Table of n, a(n) for n = 1..575
EXAMPLE
3^2 = 1^3 + 2^3; 24^2 = 4^3 + 8^3.
PROG
(Sage)
L = []
for k in range(1, 10^3):
for l in range(k + 1, 10^3):
if is_square(k**3+l**3):
L.append(sqrt(k**3+l**3))
(Python)
def aupto(limit):
c = [i**3 for i in range(1, int(limit**(2/3))+2) if i**3 <= limit**2]
cc = [c1 + c2 for i, c1 in enumerate(c) for c2 in c[i+1:]]
return sorted([i for i in range(1, limit+1) if i*i in cc])
print(aupto(8122)) # Michael S. Branicky, Mar 24 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Daniel Arribas, Dec 08 2014
STATUS
approved