OFFSET
1,2
MATHEMATICA
p[n_] := n*(n + 1); m = 1000; Select[Union[ Times @@@ Tuples[p /@ Range[0, m], {2}]], # <= 2*p[m] && PalindromeQ[#] &] (* Amiram Eldar, Aug 13 2021 *)
PROG
(SageMath)
# the sequence numbers up to a limit
def a346919_upto(lim, alst=set([0])):
for i in range(1, int(lim**0.25)):
for j in range(i, int((lim/(i*(i+1)))**0.5)+1):
if all([(k:=i*(i+1)*j*(j+1))<=lim, str(k)==str(k)[::-1]]): alst.add(k)
return sorted(alst)
print(a346919_upto(10**9)) # Dumitru Damian, Apr 05 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Dumitru Damian, Aug 07 2021
EXTENSIONS
More terms from Jinyuan Wang, Aug 07 2021
STATUS
approved