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A272611 a(1)=1; thereafter a(n) = a(n-a(n-1)) + A272612(n-1).

%I A272611 #11 May 04 2016 01:04:12
%S A272611 1,2,3,3,4,5,5,7,5,8,8,7,10,8,10,12,9,11,15,9,14,16,11,19,13,18,13,19,
%T A272611 19,18,19,20,20,18,19,20,20,23,27,20,26,28,20,35,20,31,27,26,26,37,21,
%U A272611 33,24,35,23,37,24,35,38,33,34,39,39,29,39,32,38,39,37
%N A272611 a(1)=1; thereafter a(n) = a(n-a(n-1)) + A272612(n-1).
%C A272611 Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
%C A272611 Empirically, this sequence appears to grow approximately like n/2 with a lot of noise.
%C A272611 a(n) exists for n<=10^7.
%H A272611 Nathan Fox, <a href="/A272611/b272611.txt">Table of n, a(n) for n = 1..10000</a>
%p A272611 #Code for A272611, A272612, and A272613
%p A272611 A272611:=proc(n) option remember:
%p A272611     if n = 1 then
%p A272611         return 1:
%p A272611     else
%p A272611         return A272611(n-A272611(n-1))+A272612(n-1):
%p A272611     fi:
%p A272611 end:
%p A272611 A272612:=proc(n) option remember:
%p A272611     if n = 0 then
%p A272611         return 1:
%p A272611     elif n = 1 then
%p A272611         return 1:
%p A272611     else
%p A272611         return A272612(n-A272611(n))+A272612(n-A272611(n-1)):
%p A272611     fi:
%p A272611 end:
%p A272611 A272613:=proc(n) option remember:
%p A272611     if n = 0 then
%p A272611         return 1:
%p A272611     else
%p A272611         return A272613(n-A272611(n))+A272613(n-A272612(n)):
%p A272611     fi:
%p A272611 end:
%Y A272611 Cf. A005185, A272610, A272612, A272613.
%K A272611 nonn
%O A272611 1,2
%A A272611 _Nathan Fox_, May 03 2016