

A185137


Trirecursive sequence: a(n) = a(a(a(n1))) + 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
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OFFSET

1,7


COMMENTS

The sequence is a selfsimilar 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(n1) <= a(n) for n <= 64, but a(65)a(64) = 3235 < 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 Hofstadtertype 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 !! (n1)
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



