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 A061363 #5 Mar 05 2015 12:23:38 %S A061363 9,4,18,167,2401,4086461727,14079962896835441528, %T A061363 309880704108832516500624685064706000856, %U A061363 4681896102766617737298881383797502847166028831212571921983062786215145771871779 %N A061363 a(1) = 9; a(n) = least number such that the concatenation a(n)a(n-1)...a(2)a(1) is a square. %e A061363 a(3)a(2)a(1) = 1849 = 43^2, a(4)a(3)a(2)a(1) = 1671849 = 1293^2. %Y A061363 Cf. A050638, A050639, A061359, A061361. %K A061363 nonn,base %O A061363 1,1 %A A061363 _Amarnath Murthy_, Apr 28 2001 %E A061363 Corrected by Larry Reeves (larryr(AT)acm.org), May 07 2001 %E A061363 More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Nov 06 2001