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A048040 Number of nonempty subsets of {1,2,...,n} in which exactly 2/3 of the elements are <= (n+1)/3. 0
0, 0, 0, 0, 3, 4, 5, 15, 18, 21, 63, 76, 90, 270, 325, 385, 1155, 1390, 1651, 5005, 6027, 7175, 21875, 26348, 31416, 96288, 116010, 138510, 426303, 513729, 614019, 1896279, 2285569, 2734171, 8468163, 10208110, 12220780, 37941280 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..38.

CROSSREFS

Sequence in context: A330138 A051530 A240670 * A051033 A242787 A031199

Adjacent sequences:  A048037 A048038 A048039 * A048041 A048042 A048043

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified April 5 10:20 EDT 2020. Contains 333239 sequences. (Running on oeis4.)