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..1000
EXAMPLE
a(6) = 15 = 1 + 2 + 3 + 4 + 5 = 5*6/2, because it is the least number >5 with a unique sum of 5 distinct earlier terms.
a(7) = 25 = 1 + 2 + 3 + 4 + 15 = 5^2, because it is the least number >15 with a unique sum of 5 distinct earlier terms.
MAPLE
# see A183534 for programs.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post and Alois P. Heinz, Jan 05 2011
STATUS
approved