A048047 - OEIS

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A048047

Number of nonempty subsets of {1,2,...,n} in which exactly 1/6 of the elements are <= (n+1)/3.

0

0, 0, 0, 0, 0, 0, 2, 3, 18, 63, 84, 224, 504, 630, 1270, 2420, 2937, 5742, 12012, 15015, 35035, 84119, 108164, 260064, 601664, 767244, 1720944, 3755844, 4738410, 10329750, 22591800, 28583709, 64071194, 144780009, 184657869

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

OFFSET

1,7

LINKS

Table of n, a(n) for n=1..35.

CROSSREFS

Sequence in context: A211867 A003693 A216628 * A114165 A166510 A288492

Adjacent sequences: A048044 A048045 A048046 * A048048 A048049 A048050

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved