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 A132172 #11 May 25 2015 06:27:56
%S A132172 1,1,1,1,1,2,3,4,5,6,6,7,7,8,8,10,9,11,10,13,10,14,12,15,13,17,13,18,
%T A132172 14,19,15,19,16,24,16,23,19,24,16,30,17,25,21,30,16,33,22,30,20,43,15,
%U A132172 38,20,48,10,50,13,40,16,73
%N A132172 a(1) = ... = a(5) = 1; for n >= 6, a(n)=a(n-a(n-1))+a(n-a(n-5)).
%C A132172 a(61) is undefined.
%H A132172 B. Balamohan, A. Kuznetsov and S. Tanny, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL10/Tanny/tanny3.html">On the behavior of a variant of Hofstadter's Q-sequence</a>, J. Integer Sequences, Vol. 10 (2007), #07.7.1.
%H A132172 <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>
%p A132172 a := proc(n) option remember; if n<=5 then 1 else if n > a(n-1) and n > a(n-5) then RETURN(a(n-a(n-1))+a(n-a(n-5))); else ERROR(" died at n= ", n); fi; fi; end;
%K A132172 nonn,fini,full
%O A132172 1,6
%A A132172 _T. D. Noe_ and _N. J. A. Sloane_, Nov 06 2007