A123090 a(1)=1. For n>=2, a(n) = a(n-1) + (largest divisor of n which occurs among the earlier terms of the sequence).

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

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Example

The largest divisor of 9 which occurs among the first 8 terms of the sequence is 3. So a(9) = a(8) + 3 = 19.

Mathematica

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 *)

Crossrefs

Sequence in context: A252353 A241167 A083571 * A129281 A289536 A022426

Adjacent sequences: A123087 A123088 A123089 * A123091 A123092 A123093

Keyword

nonn

Author

Leroy Quet, Sep 27 2006

Extensions

Extended by Ray Chandler, Sep 30 2006

Status

approved