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A123089 a(1)=1. For n>=2, a(n) = n + (largest divisor of n which occurs among the earlier terms of the sequence). 0
1, 3, 6, 5, 10, 12, 8, 16, 12, 20, 12, 24, 14, 28, 20, 32, 18, 36, 20, 40, 24, 23, 46, 48, 30, 27, 54, 56, 30, 60, 32, 64, 36, 35, 70, 72, 38, 76, 42, 80, 42, 84, 44, 88, 50, 92, 48, 96, 50, 100, 54, 53, 106, 108, 60, 112, 60, 59, 118, 120, 62, 124, 66, 128, 70, 132, 68, 136 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

The largest divisor of 9 which occurs among the first 8 terms of the sequence is 3. So a(9) = 9 + 3 = 12.

MATHEMATICA

f[l_List] := Block[{n = Length[l] + 1}, Append[l, n + Max[Select[l, Mod[n, # ] == 0 &]]]]; Nest[f, {1}, 100] (* Ray Chandler, Sep 30 2006 *)

CROSSREFS

Sequence in context: A298818 A196068 A242239 * A246978 A127780 A350661

Adjacent sequences: A123086 A123087 A123088 * A123090 A123091 A123092

KEYWORD

nonn

AUTHOR

Leroy Quet, Sep 27 2006

EXTENSIONS

Extended by Ray Chandler, Sep 30 2006

STATUS

approved

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Last modified February 8 02:43 EST 2023. Contains 360133 sequences. (Running on oeis4.)