A160275 Partition of positive numbers into shortest possible groups (1), (2,3), (4,5,6), (7,8), ... such that a(n) = the sum of the terms of the n-th group is a multiple of a(n-1).

1, 5, 15, 15, 30, 210, 1050, 6300, 1045800, 13756453200, 67826316310678800, 8622353329220210792550912000, 92206830102396929163916671718833533307592704000

Offset

1,2

Links

Table of n, a(n) for n=1..13.

Formula

a(n) = A000217(A160277(n)) - A000217(A160277(n-1))

Crossrefs

Cf. A160276 (ratios a(n)/a(n-1)), A160277 (last terms in the groups), A075631, A079798.

Sequence in context: A321775 A166621 A330082 * A200858 A184288 A015666

Adjacent sequences: A160272 A160273 A160274 * A160276 A160277 A160278

Keyword

nonn

Author

Max Alekseyev, May 08 2009

Status

approved