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Successive differences of Hofstadter Q-sequence.
7

%I #16 Jan 27 2014 14:26:31

%S 0,1,1,0,1,1,0,1,0,0,2,0,0,2,-1,1,1,0,1,0,0,0,4,-2,0,2,0,0,0,4,-3,0,3,

%T 1,-2,1,2,-1,1,1,0,1,0,0,0,0,8,-8,1,5,-2,-2,4,0,-2,4,-2,2,0,0,0,8,-7,

%U -2,7,-3,-2,6,1,-3,1,2,-1,1,-1,3,-2,1,2,1,-1,0,3,-2,1,2,0,-1,2,0,0,0,0,0,16,-23,11,2,2

%N Successive differences of Hofstadter Q-sequence.

%C a(A081829(n))<0; a(A081828(n))=0; a(A081830(n))>0; a(A194626(n))=1. [_Reinhard Zumkeller_, Sep 15 2011]

%H Reinhard Zumkeller, <a href="/A081827/b081827.txt">Table of n, a(n) for n = 1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HofstadtersQ-Sequence.html">Hofstadter's Q-Sequence</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Hofstadter_sequence">Hofstadter sequence</a>

%H <a href="/index/Ho#Hofstadter">Index entries for Hofstadter-type sequences</a>

%F a(n)=A005185(n+1)-A005185(n).

%o (Haskell)

%o a081827 n = a081827_list !! (n-1)

%o a081827_list = zipWith (-) (tail a005185_list) a005185_list

%o b081827 = bFile "A081827" a081827_list 1 10000 -- (0.34 secs)

%o -- _Reinhard Zumkeller_, Sep 15 2011

%K sign,look

%O 1,11

%A _Benoit Cloitre_, Apr 10 2003