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 A054049 #8 Aug 12 2017 08:13:25 %S A054049 1,1,2,3,6,13,5,9,377,21,11,89,14,8,233,16,987,18,2584,20,6765,55,23, %T A054049 28657,25,75025,27,196418,29,514229,31,1346269,33,3524578 %N A054049 Earliest sequence with a(a(n)) = Fibonacci(n+1). %C A054049 a(34) > 10^69. %H A054049 <a href="/index/Aa#aan">Index entries for sequences of the a(a(n)) = 2n family</a> %e A054049 a(a(5)) = a(13) = 8. %Y A054049 Cf. A000045. %K A054049 nice,nonn %O A054049 0,3 %A A054049 _Henry Bottomley_, Apr 28 2000