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 A353080 #15 Jan 10 2023 20:26:40
%S A353080 1429,1537,1692,1823,2001,2312,2467,2729,2858,3148,3242,3635,3849,
%T A353080 4002,4541,4552,5851,6003,6216,6296,6375,7145,7152,7159,7698,8004,
%U A353080 9093,9104,9235,9444,10005,10154,12006,12335,13645,14007,14290,14325,15272,15370,16008,16531
%N A353080 Numbers whose squares have the first three digits the same as the next three digits.
%H A353080 Alois P. Heinz, <a href="/A353080/b353080.txt">Table of n, a(n) for n = 1..10000</a>
%e A353080 1429^2 = 2042041 and 1537^2 = 2362369. Thus, 1429 and 1537 are both in this sequence.
%p A353080 q:= n-> (s-> is(s[1..3]=s[4..6]))(""||(n^2)):
%p A353080 select(q, [$317..17000])[]; # _Alois P. Heinz_, Apr 22 2022
%t A353080 Select[Range[317, 20000], Take[IntegerDigits[#^2], {1, 3}] == Take[IntegerDigits[#^2], {4, 6}] &]
%o A353080 (Python)
%o A353080 def ok(n): s = str(n**2); return len(s) > 5 and s[:3] == s[3:6]
%o A353080 print([k for k in range(20000) if ok(k)]) # _Michael S. Branicky_, Apr 22 2022
%Y A353080 Cf. A123912, A353081.
%K A353080 nonn,base
%O A353080 1,1
%A A353080 _Tanya Khovanova_, Apr 22 2022