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A087722 Strictly decreasing domain set of the Hofstadter batrachian sequence A005185. 1
9, 14, 17, 19, 21, 24, 26, 28, 30, 31, 33, 35, 37, 39, 40, 41, 43, 44, 46, 48, 50, 52, 53, 55, 57, 58, 61, 62, 63, 64, 65, 68, 69, 71, 72, 73, 75, 76, 77, 78, 79, 82, 83, 84, 86, 87, 88, 90, 92, 93, 94, 100, 104, 105, 106, 107, 108, 109, 110, 112, 113, 114, 116, 118, 119 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The third set of the Hofstadter domain.

LINKS

Table of n, a(n) for n=1..65.

FORMULA

a[n] =a[n - a[n-1]] + a[n - a[n-2]]

MATHEMATICA

digits=750 Hofstadter[n_Integer?Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n-1]] + Hofstadter[n - Hofstadter[n-2]] Hofstadter[1] = Hofstadter[2] = 1 a1=Table[Hofstadter[n], {n, 1, digits}]; f[x_, y_] := Abs[x-y]/; x-y<0 f[x_, y_] := 0/; x-y>=0 b=Table[If[f[a1[[n]], a1[[n-1]]]>0, a1[[n]], 0], {n, 2, digits}]; c=Delete[Union[b], 1]

CROSSREFS

Cf. A005185.

Sequence in context: A196547 A180868 A036266 * A217005 A103409 A011767

Adjacent sequences:  A087719 A087720 A087721 * A087723 A087724 A087725

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Sep 29 2003

STATUS

approved

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Last modified July 24 09:52 EDT 2021. Contains 346273 sequences. (Running on oeis4.)