login
A082429
a(n) is the cardinality of the smallest subset S1 of S={1,2,3,...,n} such that every element of S is either in S1 or is the sum of two elements of S1.
0
1, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8
OFFSET
1,2
EXAMPLE
a(6)=3 since, for S1={1,2,4}, we have 1=1, 2=2, 3=1+2, 4=4, 5=1+4 and 6=2+4 and no set S1 with fewer than three elements has the required property.
CROSSREFS
Sequence in context: A370461 A060646 A103298 * A047744 A163563 A189667
KEYWORD
nonn
AUTHOR
John W. Layman, Apr 24 2003
STATUS
approved