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%I #12 Jul 13 2013 12:02:58
%S 1,4,7,9,10,12,13,18,20,21,22,25,27,28,29,32,41,43,44,45,46,54,59,60,
%T 61,82,87,90,91,92,93,94,102,111,133,154,157,163,177,182,186,187,188,
%U 189,190,273,334,342,350,360,367,378,379,380,381,382,418,431,441,464,483
%N Numbers n such that 2 successive terms of Hofstadter Q-sequence are the same.
%C A005185(a(n)+1) = A005185(a(n)); A081827(a(n)) = 0.
%H Reinhard Zumkeller, <a href="/A081828/b081828.txt">Table of n, a(n) for n = 1..250</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>
%o (Haskell)
%o import Data.List (elemIndices)
%o a081828 n = a081828_list !! (n-1)
%o a081828_list = map (+ 1) $ elemIndices 0 a081827_list
%o -- _Reinhard Zumkeller_, Sep 15 2011
%Y Cf. A081829, A081830, A194626.
%K nonn
%O 1,2
%A _Benoit Cloitre_, Apr 10 2003
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