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A106733 a[n] =a[a[a[a[n - a[n-1]]]]] + a[n - a[n-2]]. 2
1, 1, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 9, 8, 9, 9, 9, 9, 9, 9, 9, 11, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 13, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 15, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 17, 16, 17, 17, 17, 17 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

A fifth-order recursion based on Hofstadter's Q-sequence A005185.

LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..10000

MATHEMATICA

Hofstadter1[1] = Hofstadter1[2] = 1; Hofstadter1[n_Integer?Positive] := Hofstadter1[n] = Hofstadter1[Hofstadter1[Hofstadter1[Hofstadter1[n - Hofstadter1[n - 1]]]]] + Hofstadter1[ n - Hofstadter1[n - 2]]; a = Table[Hofstadter1[n], {n, 1, digits}]

CROSSREFS

Cf. A087842, A005185.

Sequence in context: A209869 A087839 A106742 * A087838 A057627 A013940

Adjacent sequences:  A106730 A106731 A106732 * A106734 A106735 A106736

KEYWORD

nonn

AUTHOR

Roger L. Bagula, May 30 2005

STATUS

approved

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Last modified March 21 12:12 EDT 2019. Contains 321369 sequences. (Running on oeis4.)