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 A037842 #20 Jul 02 2025 16:01:56
%S A037842 1,11,111,11111,11111111,1111111111111,111111111111111111111,
%T A037842 1111111111111111111111111111111111,
%U A037842 1111111111111111111111111111111111111111111111111111111
%N A037842 Fibonacci numbers in base 1.
%F A037842 a(n+2) = concat( a(n+1), a(n) ), a(0) = 1, a(1) = 11. - corrected by _Jason Kimberley_, Dec 17 2012
%t A037842 FromDigits[Table[1,{#}]]&/@Fibonacci[Range[2,10]] (* _Harvey P. Dale_, Apr 06 2013 *)
%Y A037842 Cf. A108047, A131293.
%K A037842 nonn,easy,base
%O A037842 0,2
%A A037842 _N. J. A. Sloane_, Feb 27 2000
%E A037842 More terms from _James Sellers_, Mar 01 2000