A047191 - 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

A047191

Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= (n-2)/2.

0, 0, 0, 0, 0, 0, 2, 3, 18, 24, 84, 105, 280, 336, 756, 882, 1785, 2044, 4004, 4554, 9504, 10890, 25740, 29887, 77077, 90090, 234454, 273559, 685984, 795704, 1905904, 2196740, 5094390, 5845008

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

OFFSET

1,7

LINKS

Table of n, a(n) for n=1..34.

CROSSREFS

Sequence in context: A112664 A216890 A370362 * A096308 A073529 A134850

Adjacent sequences: A047188 A047189 A047190 * A047192 A047193 A047194

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved