A081827 Successive differences of Hofstadter Q-sequence.

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, 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, -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

Offset: 1

Author

Benoit Cloitre, Apr 10 2003

Keywords

• sign
• look

Comments

a(A081829(n))<0; a(A081828(n))=0; a(A081830(n))>0; a(A194626(n))=1. [Reinhard Zumkeller, Sep 15 2011]

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Hofstadter's Q-Sequence
• Wikipedia, Hofstadter sequence
• Index entries for Hofstadter-type sequences

Programs

Haskell

a081827 n = a081827_list !! (n-1)
a081827_list = zipWith (-) (tail a005185_list) a005185_list
b081827 = bFile "A081827" a081827_list 1 10000 -- (0.34 secs)
-- Reinhard Zumkeller, Sep 15 2011

Formula

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