This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A346919 #34 Apr 23 2023 23:40:48
%S A346919 0,4,252,2112,2772,6336,21012,27072,42924,48384,48984,63036,252252,
%T A346919 297792,407704,2327232,2572752,2747472,2774772,2958592,4457544,
%U A346919 4811184,6378736,6396936,25777752,27633672,29344392,63099036,63399336,404080404,409757904,441525144
%N A346919 Numbers that are both palindromes (A002113) and terms of A072389.
%F A346919 Intersection of A072389 and A002113.
%F A346919 Intersection of 4*A085780 and A002113.
%t A346919 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 *)
%o A346919 (SageMath)
%o A346919 # the sequence numbers up to a limit
%o A346919 def a346919_upto(lim, alst=set([0])):
%o A346919 for i in range(1, int(lim**0.25)):
%o A346919 for j in range(i, int((lim/(i*(i+1)))**0.5)+1):
%o A346919 if all([(k:=i*(i+1)*j*(j+1))<=lim, str(k)==str(k)[::-1]]): alst.add(k)
%o A346919 return sorted(alst)
%o A346919 print(a346919_upto(10**9)) # _Dumitru Damian_, Apr 05 2023
%Y A346919 Cf. A002113, A072389, A085780.
%K A346919 nonn,base
%O A346919 1,2
%A A346919 _Dumitru Damian_, Aug 07 2021
%E A346919 More terms from _Jinyuan Wang_, Aug 07 2021