A047174 - OEIS

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A047174

Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n-1)/2.

0, 0, 0, 1, 2, 8, 12, 30, 40, 86, 110, 245, 315, 756, 980, 2387, 3080, 7400, 9480, 22737, 29040, 70390, 89870, 219791, 280423, 688051, 876603, 2154347, 2741102, 6754580, 8586788, 21225758, 26965808, 66826712

(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: A115102 A257082 A265736 * A048074 A126775 A306898

Adjacent sequences: A047171 A047172 A047173 * A047175 A047176 A047177

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved