A183529 An Ulam-type sequence: a(n) = n if n<=6; for n>6, a(n) = least number > a(n-1) which is a unique sum of 6 distinct earlier terms.

1, 2, 3, 4, 5, 6, 21, 36, 37, 38, 39, 40, 41, 51, 61, 66, 284, 285, 289, 290, 297, 298, 299, 310, 312, 559, 561, 562, 570, 571, 574, 575, 834, 836, 837, 838, 839, 840, 841, 849, 850, 1109, 1124, 1125, 1126, 1127, 1386, 1401, 1402, 1661, 1676, 1677, 1936, 1951

Offset

1,2

Comments

An Ulam-type sequence - see A002858 for further information.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..700

Index entries for Ulam numbers

Example

a(7) = 21 = 1 + ... + 6 = 6*7/2, because it is the least number >6 with a unique sum of 6 distinct earlier terms.
a(8) = 36 = 1 + ... + 5 + 21 = 6^2, because it is the least number >21 with a unique sum of 6 distinct earlier terms.

Maple

# see A183534 for programs.

Crossrefs

Column k=6 of A183534.

Cf. A002858, A007086, A183527-A183533, A135737.

Sequence in context: A123678 A208450 A037333 * A342999 A037404 A037440

Adjacent sequences: A183526 A183527 A183528 * A183530 A183531 A183532

Keyword

nonn

Author

Jonathan Vos Post and Alois P. Heinz, Jan 05 2011

Status

approved