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A123090
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a(1)=1. For n>=2, a(n) = a(n-1) + (largest divisor of n which occurs among the earlier terms of the sequence).
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2
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1, 2, 3, 5, 10, 13, 14, 16, 19, 29, 30, 33, 46, 60, 65, 81, 82, 85, 104, 114, 117, 119, 120, 123, 128, 141, 144, 158, 187, 217, 218, 234, 267, 269, 274, 277, 278, 297, 310, 320, 321, 335, 336, 338, 343, 389, 390, 406, 407, 417, 420, 433, 434, 437, 442, 456, 475
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OFFSET
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1,2
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LINKS
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EXAMPLE
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The largest divisor of 9 which occurs among the first 8 terms of the sequence is 3. So a(9) = a(8) + 3 = 19.
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MATHEMATICA
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f[l_List] := Block[{n = Length[l] + 1}, Append[l, Last[l] + Max[Select[l, Mod[n, # ] == 0 &]]]]; Nest[f, {1}, 60] (* Ray Chandler, Sep 30 2006 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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