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 A087553 #10 Sep 22 2024 13:53:41 %S A087553 0,1,4,9,100,121,676,900,10000,12100,12321,90000,1000000,1210000, %T A087553 1232100,1234321,9000000,100000000,121000000,123210000,123432100, %U A087553 123454321,900000000,10000000000,11122233444,12100000000,12321000000,12343210000 %N A087553 Squares in which the neighboring digits differ at most by 1. Neighbors of 1 are 0 and 2, neighbors of 0 are 1 and 9. %C A087553 The sequence is infinite with trivial terms like 10^(2k) and 9*10^(2k). Conjecture: There are infinitely many nontrivial terms. %H A087553 Andrew Howroyd, <a href="/A087553/b087553.txt">Table of n, a(n) for n = 1..63</a> %e A087553 12321, 1345678987654321 are terms. %Y A087553 Intersection of A000290 and A376425. %K A087553 base,nonn %O A087553 1,3 %A A087553 _Amarnath Murthy_, Sep 13 2003 %E A087553 More terms from _Sascha Kurz_, Sep 22 2003 %E A087553 Offset changed and 0 inserted by _Andrew Howroyd_, Sep 22 2024