A183532 - OEIS

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

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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.

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