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 A308983 #21 Oct 04 2019 09:09:42 %S A308983 4,15,18,20,23,29,33,34,35,36,38,39,43,48,49,50,54,56,60,62,63,66,68, %T A308983 69,74,75,77,78,81,83,84,86,88,89 %N A308983 Numbers n such that A308803(2n+1) = (2*10^n-1)(5*10^n+1). %C A308983 A308803(2n+1) >= (2*10^n-1)(5*10^n+1) for all n. This sequence lists the values of n where this lower bound is attained. %Y A308983 Cf. A308803 %K A308983 nonn,base,more %O A308983 1,1 %A A308983 _Chai Wah Wu_, Sep 30 2019 %E A308983 a(14)-a(34) from _Chai Wah Wu_, Oct 03 2019