A048018 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A048018

Number of nonempty subsets of {1,2,...,n} in which exactly 2/3 of the elements are <= (n-2)/3.

0, 0, 0, 0, 0, 0, 0, 6, 7, 8, 24, 27, 30, 105, 121, 138, 450, 520, 595, 1939, 2255, 2600, 8456, 9877, 11445, 37122, 43510, 50625, 164025, 192801, 225093, 728409, 858199, 1004754, 3248322, 3834655, 4500210, 14536951, 17189667

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,8

LINKS

Table of n, a(n) for n=1..39.

CROSSREFS

Sequence in context: A358557 A112813 A347808 * A254714 A047197 A048079

Adjacent sequences: A048015 A048016 A048017 * A048019 A048020 A048021

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved