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 A068668 #15 Aug 09 2025 22:38:05
%S A068668 9,99,1881,171171,1882881,306909603,11355655311,1033364633301,
%T A068668 1034397997934301,10241574577547514201,10231343244544544234313201,
%U A068668 112544775689989986577445211,1023144555797698967975554413201,102221350448336861989168633844053122201,11233003103852144358833233885344125830130033211
%N A068668 a(1) = 9; a(n) = smallest palindromic multiple of a(n-1).
%t A068668 a[1] = 9; a[n_] := a[n] = Block[{k = 2}, While[k*a[n - 1] != ToExpression[ StringReverse[ ToString[k*a[n - 1]]]], k++ ]; k*a[n - 1]]; Table[a[n], {n, 1, 13}] (* _Robert G. Wilson v_, Apr 19 2002 *)
%Y A068668 Cf. A068664, A068665, A068666, A068667, A070069, A068971, A068972, A068973, A068974.
%K A068668 base,nonn
%O A068668 1,1
%A A068668 _Amarnath Murthy_, Mar 01 2002
%E A068668 More terms from _Sascha Kurz_, Mar 27 2002
%E A068668 Edited by _N. J. A. Sloane_, Apr 19 2007
%E A068668 a(14)-a(15) from _Giovanni Resta_, Sep 25 2019