cp's OEIS Frontend

A283883 Relative of Hofstadter Q-sequence: a(n) = max(0, n+117) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 0.

%I A283883 #6 Mar 19 2017 19:24:21
%S A283883 3,118,119,5,120,6,7,121,123,10,8,123,127,12,124,14,129,11,128,132,16,
%T A283883 13,17,15,131,20,20,242,123,24,32,238,3,32,357,5,238,3,5,595,5,238,3,
%U A283883 5,833,5,238,3,5,1071,5,238,3,5,1309,5,238,3,5,1547,5,238,3,5,1785,5,238,3,5,2023,5,238,3,5,2261
%N A283883 Relative of Hofstadter Q-sequence: a(n) = max(0, n+117) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 0.
%C A283883 Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 117 terms.
%C A283883 This sequence has exactly 3346939303954 terms (of positive index). a(3346939303954) = 0, so an attempt to calculate a(3346939303955) would refer to itself.
%H A283883 Nathan Fox, <a href="/A283883/b283883.txt">Table of n, a(n) for n = 1..10000</a>
%F A283883 If the index is between 35 and 122 (inclusive), then a(5n) = 238n-1309, a(5n+1) = 5, a(5n+2) = 238, a(5n+3) = 3, a(5n+4) = 5.
%F A283883 If the index is between 128 and 4525 (inclusive), then a(5n) = 4641, a(5n+1) = 3, a(5n+2) = 5, a(5n+3) = 4641n-106981, a(5n+4) = 5.
%F A283883 If the index is between 4531 and 4093008 (inclusive), then a(5n) = 5, a(5n+1) = 4093124n-3700188737, a(5n+2) = 5, a(5n+3) = 4093124, a(5n+4) = 3.
%F A283883 If the index is between 4093008 and 3346939303796 (inclusive), then a(5n) = 5, a(5n+1) = 3346939303911, a(5n+2) = 3, a(5n+3) = 5, a(5n+4) = 3346939303911n-2739804514185637724.
%p A283883 A283883:=proc(n) option remember: if n <= 0 then max(0, n+117): else A283883(n-A283883(n-1)) + A283883(n-A283883(n-2)): fi: end:
%Y A283883 Cf. A005185, A274058, A283883.
%K A283883 nonn,fini
%O A283883 1,1
%A A283883 _Nathan Fox_, Mar 19 2017