A126698 a(0)=1. For n>=1, a(n) = a(n-1) + (largest divisor of n which does not occur among the earlier terms of the sequence); or a(n) = a(n-1) if every divisor of n occurs among the earlier terms of the sequence.

1, 1, 3, 3, 7, 12, 18, 18, 26, 35, 45, 56, 62, 75, 89, 104, 120, 137, 146, 165, 185, 206, 228, 251, 275, 300, 313, 340, 368, 397, 427, 458, 490, 523, 557, 562, 598, 635, 673, 712, 752, 793, 835, 878, 922, 937, 983, 1030, 1078, 1127, 1177, 1228, 1280, 1333

Offset

0,3

Links

Table of n, a(n) for n=0..53.

Mathematica

f[l_List] := Block[{c}, c = Complement[Divisors[Length[l]], l]; Append[l, l[[ -1]] + If[c == {}, 0, Max @@ c]]]; Nest[f, {1}, 55] (* Ray Chandler, Feb 19 2007 *)

Crossrefs

Sequence in context: A006661 A343752 A068626 * A219211 A088859 A177942

Adjacent sequences: A126695 A126696 A126697 * A126699 A126700 A126701

Keyword

nonn

Author

Leroy Quet, Feb 15 2007

Extensions

Extended by Ray Chandler, Feb 19 2007

Status

approved