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 distinct elements of S1.

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, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12

Offset

1,2

Links

Table of n, a(n) for n=1..56.

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

Adjacent sequences: A082426 A082427 A082428 * A082430 A082431 A082432

Keyword

nonn,more

Author

John W. Layman, Apr 24 2003

Extensions

Name clarified and a(28)-a(56) from Sean A. Irvine, Dec 07 2025

Status

approved