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A047163 Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= n/2. 0
0, 0, 0, 0, 2, 3, 12, 16, 40, 50, 110, 135, 315, 392, 980, 1232, 3080, 3864, 9480, 11850, 29040, 36300, 89870, 112519, 280423, 351351, 876603, 1098188, 2741102, 3433703, 8586788, 10758608, 26965808, 33794504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

CROSSREFS

Sequence in context: A123761 A181121 A333319 * A046486 A073452 A112976

Adjacent sequences:  A047160 A047161 A047162 * A047164 A047165 A047166

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified January 26 10:18 EST 2021. Contains 340435 sequences. (Running on oeis4.)