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 A088780 #12 Nov 25 2024 00:56:10 %S A088780 9,99,9009,909909,9009009009,90099099099009,90009090099009090009, %T A088780 9000009009009009009009000009,90000090099090099099099009099009000009 %N A088780 a(1) = 9, a(n) = smallest palindromic multiple of a(n-1) obtained by inserting digits anywhere in a(n-1). %Y A088780 Cf. A082776, A082777, A082778, A082779, A082781, A082782, A082783. %K A088780 nonn,base,more %O A088780 1,1 %A A088780 _Ray Chandler_, Oct 26 2003 %E A088780 a(8) from _David Consiglio, Jr._, Sep 30 2022 %E A088780 a(9) from _Max Alekseyev_, Nov 24 2024