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A185137 Tri-recursive sequence: a(n) = a(a(a(n-1))) + a(n - a(a(-3+n))) if n>6, otherwise a(n) = 1. 1
1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 12, 13, 14, 15, 15, 15, 15, 15, 15, 16, 17, 18, 20, 20, 20, 20, 20, 20, 20, 21, 22, 23, 26, 26, 26, 26, 26, 26, 26, 26, 27 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

COMMENTS

The sequence is a self-similar staircase chaotic sequence with correlation dimension near 1.4044050877368695 as determined using correlation dimension program by Mark J. McCready (USAMark.J.McCready.1(AT)nd.edu).

a(n-1) <= a(n) for n <= 64, but a(65)-a(64) = 32-35 < 0; first positions m where a(m) > a(m+1): 64, 79, 84, 99, 105, 106, 110, 125, 126, ... . - Reinhard Zumkeller, Jun 13 2013

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for Hofstadter-type sequences

MATHEMATICA

a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[5] = 1; a[6] = 1;

a[n_] := a[n] = a[a[a[n - 1]]] + a[n - a[a[-3 + n]]]

b = Table[a[n], {n, 1, 300}]

PROG

(Haskell)

a185137 n = a185137_list !! (n-1)

a185137_list = 1 : 1 : 1 : 1 : 1 : 1 : f 7 1 1 where

   f x u v = w : f (x + 1) v w where

             w = (a185137 . a185137 . a185137) (x - 1) +

                 a185137 (x - (a185137 . a185137) (x - 3))

-- Reinhard Zumkeller, Jun 13 2013

CROSSREFS

Cf. A209384, A087831.

Sequence in context: A225673 A257779 A285762 * A137180 A258632 A263283

Adjacent sequences:  A185134 A185135 A185136 * A185138 A185139 A185140

KEYWORD

nonn,look

AUTHOR

Roger L. Bagula, Mar 12 2012

STATUS

approved

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Last modified April 24 16:06 EDT 2019. Contains 322430 sequences. (Running on oeis4.)