A183532 An Ulam-type sequence: a(n) = n if n<=9; for n>9, a(n) = least number > a(n-1) which is a unique sum of 9 distinct earlier terms.

1, 2, 3, 4, 5, 6, 7, 8, 9, 45, 81, 82, 83, 84, 85, 86, 87, 88, 89, 117, 133, 153, 177, 189, 221, 225, 1325, 1326, 1328, 1329, 1373, 1378, 1379, 1391, 1392, 1398, 1423, 1427, 2717, 2718, 4031, 4032, 4035, 4037, 4039, 5316, 5319, 5346, 5352, 5353, 5354, 5361

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..200

Index entries for Ulam numbers

Example

a(10) = 45 = 1 + ... + 9 = 9*10/2, because it is the least number >9 with a unique sum of 9 distinct earlier terms.
a(11) = 81 = 1 + ... + 8 + 45 = 9^2, because it is the least number >45 with a unique sum of 9 distinct earlier terms.

Maple

# see A183534 for programs.

Crossrefs

Column k=9 of A183534.

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

Sequence in context: A129513 A281745 A302501 * A257829 A219327 A219326

Adjacent sequences: A183529 A183530 A183531 * A183533 A183534 A183535

Keyword

nonn

Author

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

Status

approved