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 A263610 #4 Oct 22 2015 14:28:07 %S A263610 0,1,121,10201,12321,1002001,1032301,1223221,100020001,102030201, %T A263610 103101301,120202021,10000200001,10033233001,1000002000001, %U A263610 1002003002001,1003010103001,1021320231201,1211130311121,1212110112121,1213332333121,100000020000001,100033323330001,100331000133001 %N A263610 Palindromes in base 4 which are also squares. %H A263610 G. J. Simmons, <a href="/A002778/a002778.pdf">On palindromic squares of non-palindromic numbers</a>, J. Rec. Math., 5 (No. 1, 1972), 11-19. [Annotated scanned copy] %Y A263610 Cf. A002778, A003166, A029986, A262609, A029987. %K A263610 nonn,base %O A263610 1,3 %A A263610 _N. J. A. Sloane_, Oct 22 2015