login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A066063 Size of the smallest subset S of T={0,1,2,...,n} such that each element of T is the sum of two elements of S. 2
1, 2, 2, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

If one counts all subsets S of T={0,1,2,...n} such that each number in T is the sum of two elements of S, sequence A066062 is obtained.

Since each k-subset of S covers at most binom(k + 1, 2) members of T, we have binom(A066063(n) + 1, 2) >= n + 1. It follows that A002024(n-1) is a lower bound. - Rob Pratt, May 14 2004

This is an instance of the <= 2-stamp postage problem with n denominations. For n > 0, A066063(n) = 1 + the smallest i such that A001212(i) >= n (adding one adjusts for the fact that A001212 has offset 1). - Tim Peters (tim.one(AT)comcast.net), Aug 25 2006

LINKS

Table of n, a(n) for n=0..26.

EXAMPLE

For n=2, it is clear that S={0,1} is the unique subset of {0,1,2} that satisfies the definition, so a(2)=2.

CROSSREFS

Cf. A066062.

Cf. A002024.

Cf. A001212.

Sequence in context: A277903 A102515 A276571 * A123087 A071868 A179390

Adjacent sequences:  A066060 A066061 A066062 * A066064 A066065 A066066

KEYWORD

nonn

AUTHOR

John W. Layman, Dec 01 2001

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified September 24 18:54 EDT 2017. Contains 292433 sequences.