A048020 - OEIS

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A048020

Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= (n-2)/3.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 9, 10, 40, 44, 48, 120, 130, 140, 371, 405, 440, 1400, 1547, 1701, 5292, 5852, 6440, 18780, 20734, 22792, 66550, 73600, 81080, 242792, 269225, 297440, 892970, 991314, 1096627, 3265171, 3626363

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

OFFSET

1,11

LINKS

Table of n, a(n) for n=1..42.

CROSSREFS

Sequence in context: A308809 A272142 A270039 * A363760 A048000 A048081

Adjacent sequences: A048017 A048018 A048019 * A048021 A048022 A048023

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved