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 A138845 #2 Mar 30 2012 17:27:55 %S A138845 1,10,115,201,1015,1029,10029,100021 %N A138845 First gap of length at least n in A137292, lower end. %e A138845 First few terms of A137292 are 1,3,4,5,7,8,10,13,14,15,17,... . The first gap of length 1 is between 1 and 3, hence a(1) = 1; the first gap of length 2 is between 10 and 13, hence a(2) = 10. %Y A138845 Cf. A137292, A138662. %K A138845 nonn,base %O A138845 1,2 %A A138845 _Klaus Brockhaus_, Mar 31 2008