A087828 - OEIS

A087828

a(n) = a(Min(n-1,Abs(n - a(n-1)))) + a(a(Abs(n - a(n-3))))

1, 1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 6, 5, 6, 6, 6, 6, 9, 6, 9, 9, 8, 9, 9, 9, 9, 13, 9, 13, 9, 11, 12, 13, 13, 12, 13, 13, 13, 13, 19, 12, 15, 13, 15, 13, 19, 13, 16, 17, 19, 16, 17, 19, 18, 19, 19, 19, 19, 28, 16, 19, 19, 21, 19, 28, 19, 22, 28, 21, 23, 22, 25, 25, 23, 26, 25, 23, 25

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OFFSET

0,4

COMMENTS

A second triple recursion sequence of the Hofstadter Q skip one.

LINKS

Table of n, a(n) for n=0..78.

MATHEMATICA

Hofstadter3[n_Integer?Positive] := Hofstadter3[n] = Hofstadter3[Min[n-1, Abs[n - Hofstadter3[n-1]]]] + Hofstadter3[Hofstadter3[Abs[n - Hofstadter3[n-3]]]] Hofstadter3[0]=Hofstadter3[1] = Hofstadter3[2]= Hofstadter3[3]= 1 digits=200 ta=Table[Hofstadter3[n], {n, 1, digits}]

CROSSREFS

Cf. A005185.

Sequence in context: A087817 A091497 A005707 * A330779 A366632 A110867

Adjacent sequences: A087825 A087826 A087827 * A087829 A087830 A087831

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Oct 06 2003

STATUS

approved