A075086 Rearrangement of natural numbers such that the n-th partial sum is divisible by the n-th composite number.

4, 2, 10, 11, 3, 6, 20, 19, 5, 28, 12, 27, 7, 14, 32, 8, 35, 9, 18, 50, 43, 45, 47, 13, 26, 52, 54, 30, 74, 16, 62, 34, 17, 67, 69, 71, 40, 75, 21, 78, 22, 44, 106, 23, 87, 24, 90, 118, 95, 97, 56, 130, 29, 105, 107, 31, 142, 113, 33, 66, 203, 121, 36, 124, 164, 38, 222, 133, 41

Offset

1,1

Links

Table of n, a(n) for n=1..69.

Mathematica

Composite[n_Integer] := FixedPoint[1 + n + PrimePi@ # &, n + PrimePi@ n + 1]; f[s_List] := Block[{c = Composite[1 + Length@ s], k = 1, t = Plus @@ s}, While[ MemberQ[s, k] || Mod[t + k, c] > 0, k++]; Append[s, k]]; Nest[f, {}, 69] (* Robert G. Wilson v, May 13 2011 *)

Crossrefs

Sequence in context: A121794 A250108 A210735 * A284782 A128781 A135440

Adjacent sequences: A075083 A075084 A075085 * A075087 A075088 A075089

Keyword

nonn

Author

Amarnath Murthy, Sep 13 2002

Extensions

More terms from David Wasserman, Jan 16 2005

Status

approved