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 A288854 #23 Jun 19 2017 12:03:21 %S A288854 25,625,5625,75625,275625 %N A288854 The unique longest sequence of squares where each number (after the first) is obtained by prefixing a single digit to its predecessor. %C A288854 This chain with five squares is the longest which exists in this context, there is no such sequence of length >= 6. %C A288854 There are also only four chains of maximal length 4 with: %C A288854 -> 25, 225, 1225, 81225. These four squares are the first terms of A061839. %C A288854 -> 25, 225, 4225, 34225. %C A288854 -> 25, 225, 7225, 27225. These four squares are the first terms of A191486. %C A288854 -> 25, 625, 5625, 15625. %C A288854 There are also only three chains of maximal length 3 with: %C A288854 -> 3025, 93025, 893025. %C A288854 -> 30625, 330625, 3330625. %C A288854 -> 50625, 950625, 4950625. %C A288854 See Crux Mathematicorum links. %H A288854 L. Csirmaz, <a href="https://cms.math.ca/crux/backfile/Crux_v7n09_Nov.pdf">Problem 526, solution</a>, Crux Mathematicorum, page 280, Vol.7, Nov. 81. %H A288854 Friend H. Kierstead, Jr., <a href="https://cms.math.ca/crux/backfile/Crux_v7n03_Mar.pdf">Problem 526, partial solution</a>, Crux Mathematicorum, page 87, Vol.7, Mar. 81. %e A288854 25 = 5^2; 625 = 25^2; 5625 = 75^2; 75625 = 275^2; 275625 = 525^2. %Y A288854 Cf. A061839, A191486. %K A288854 nonn,fini,full,base %O A288854 1,1 %A A288854 _Bernard Schott_, Jun 18 2017