A088099 Group the natural numbers with at least two members in each group such that the n-th group sum is a multiple of n: (1, 2), (3, 4, 5), (6, 7, 8), (9, 10, 11, 12, 13, 14, 15), (16, 17, 18, 19), (20, 21, 22, 23, 24, 25, 26, 27, 28), (29, 30, 31, 32, 33, 34), ... Sequence contains the group sums.

3, 12, 21, 84, 70, 216, 189, 440, 396, 280, 242, 192, 858, 1092, 465, 3568, 2312, 1188, 2907, 3420, 1155, 990, 2691, 1080, 2925, 1170, 3159, 1260, 3393, 1350, 3627, 1440, 3861, 1530, 4095, 1620, 4329, 1710, 4563, 1800, 4797, 1890, 5031, 1980, 5265, 2070

Offset

1,1

Comments

The condition 'at least two terms' is imposed to avoid the trivial grouping (1),(2),(3),(4),(5),... a(n) == 0 (mod n) by definition.

Links

Table of n, a(n) for n=1..46.

Crossrefs

Cf. A088100, A088101.

Sequence in context: A061262 A051656 A074004 * A110419 A031223 A063598

Adjacent sequences: A088096 A088097 A088098 * A088100 A088101 A088102

Keyword

nonn

Author

Amarnath Murthy, Sep 24 2003

Extensions

More terms from Ray Chandler, Sep 26 2003

Status

approved