A081828 Numbers n such that 2 successive terms of Hofstadter Q-sequence are the same.

1, 4, 7, 9, 10, 12, 13, 18, 20, 21, 22, 25, 27, 28, 29, 32, 41, 43, 44, 45, 46, 54, 59, 60, 61, 82, 87, 90, 91, 92, 93, 94, 102, 111, 133, 154, 157, 163, 177, 182, 186, 187, 188, 189, 190, 273, 334, 342, 350, 360, 367, 378, 379, 380, 381, 382, 418, 431, 441, 464, 483

Offset

1,2

Comments

A005185(a(n)+1) = A005185(a(n)); A081827(a(n)) = 0.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..250

Eric Weisstein's World of Mathematics, Hofstadter's Q-Sequence

Wikipedia, Hofstadter sequence

Index entries for Hofstadter-type sequences

Prog

(Haskell)
import Data.List (elemIndices)
a081828 n = a081828_list !! (n-1)
a081828_list = map (+ 1) $ elemIndices 0 a081827_list
-- Reinhard Zumkeller, Sep 15 2011

Crossrefs

Cf. A081829, A081830, A194626.

Sequence in context: A123573 A085746 A324599 * A287678 A335229 A310939

Adjacent sequences: A081825 A081826 A081827 * A081829 A081830 A081831

Keyword

nonn

Author

Benoit Cloitre, Apr 10 2003

Status

approved