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 A124290 #14 Dec 15 2024 14:33:58 %S A124290 11,109,1087,10867,108649,1086469,10864669,108646667,1086466657, %T A124290 10864666531,108646665307,1086466653067,10864666530661, %U A124290 108646665306581,1086466653065803,10864666530658001,108646665306579997,1086466653065799961,10864666530657999467,108646665306579994669 %N A124290 Largest prime < 10*a(n-1), a(1)=11. %H A124290 Vincenzo Librandi, <a href="/A124290/b124290.txt">Table of n, a(n) for n = 1..200</a> %t A124290 NestList[NextPrime[10#,-1]&,11,20] (* _Harvey P. Dale_, Mar 09 2011 *) %Y A124290 Cf. A124262. %K A124290 nonn %O A124290 1,1 %A A124290 _Artur Jasinski_, Dec 16 2006