A278059 - OEIS

%I #17 May 30 2024 03:04:52

%S 1,2,3,4,5,6,7,3,8,9,5,10,6,7,11,13,10,8,13,17,7,16,20,7,13,19,10,16,

%T 19,12,23,25,12,24,25,15,26,30,14,28,16,26,20,15,25,30,26,24,33,29,24,

%U 36,29,21,43,31,26,35,19,29,51,17,40,33,38,28

%N Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 7; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 7.

%C Similar to Hofstadter's Q-sequence A005185 but with different starting values.

%C Much like the Hofstadter Q-sequence, it is not known if this sequence is defined for all positive n.

%C a(n) exists for n <= 3*10^7.

%H Nathan Fox, <a href="/A278059/b278059.txt">Table of n, a(n) for n = 1..10000</a>

%H Nathan Fox, <a href="https://vimeo.com/191094180">Hofstadter-like Sequences over Nonstandard Integers</a>, Talk given at the Rutgers Experimental Mathematics Seminar, November 10 2016.

%t a[n_] := a[n] = If[0 < n < 8, n, a[n-a[n-1]] + a[n-a[n-2]]];

%t Array[a, 100] (* _Paolo Xausa_, May 29 2024 *)

%Y Cf. A005185, A278056, A278057, A278058, A278060, A278061, A278062, A278063, A278064, A278065.

%K nonn

%O 1,2

%A _Nathan Fox_, Nov 10 2016