cp's OEIS Frontend

A373230 Relative of Hofstadter Q-sequence: a(n) = 0 for n <= 0, a(n) = n for 1 <= n <= 10; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 10.

%I A373230 #10 May 31 2024 14:33:07
%S A373230 1,2,3,4,5,6,7,8,9,10,6,11,12,13,9,14,15,16,12,17,18,19,15,20,21,17,
%T A373230 23,18,23,25,26,22,21,31,29,21,28,34,27,29,31,27,38,33,34,31,39,37,37,
%U A373230 30,44,36,39,35,43,45,43,30,50,50,38,42,51,48,43,40,55,51,52,37,60,57,47
%N A373230 Relative of Hofstadter Q-sequence: a(n) = 0 for n <= 0, a(n) = n for 1 <= n <= 10; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 10.
%C A373230 Similar to A278055 but with different starting values.
%C A373230 a(1015) = 1036. This is the smallest index for which a(n) > n. So, without the condition that a(n) = 0 for n <= 0, this sequence would be finite and have exactly 1015 terms.
%C A373230 Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.
%C A373230 a(n) exists for n <= 3*10^7.
%H A373230 Nathan Fox, <a href="/A373230/b373230.txt">Table of n, a(n) for n = 1..10000</a>
%t A373230 a[n_] := a[n] = Which[n < 1, 0, n < 11, n, True, a[n-a[n-1]] + a[n-a[n-2]] + a[n-a[n-3]]]; Array[a, 100] (* _Paolo Xausa_, May 31 2024 *)
%Y A373230 Cf. A005185, A278055, A373227, A373228, A373229, A373231, A373232, A373233.
%Y A373230 Similar sequences based on the Q-recurrence: A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.
%K A373230 nonn
%O A373230 1,2
%A A373230 _Nathan Fox_, May 28 2024