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 A098209 #7 Jun 27 2020 16:37:19 %S A098209 0,48,4488,444888,44448888,4444488888,444444888888,44444448888888, %T A098209 4444444488888888,444444444888888888,44444444448888888888, %U A098209 4444444444488888888888,444444444444888888888888 %N A098209 a(n) = A067275(n+1)^2 - 1. %C A098209 Certain functions of near or generalized repdigits provide interesting digit patterns like e.g: -1+(666666667)^2=444444444888888888. %Y A098209 Cf. A067275, A096507. %K A098209 nonn %O A098209 0,2 %A A098209 _Labos Elemer_, Oct 20 2004 %E A098209 Definition corrected by _Georg Fischer_, Jun 27 2020