A048019 Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n-2)/3.

0, 0, 0, 0, 4, 10, 20, 41, 77, 140, 252, 505, 1000, 1780, 3652, 7305, 12545, 25805, 52325, 88634, 184736, 379676, 636524, 1334942, 2764139, 4594244, 9685364, 20191604, 33355944, 70639794, 148064400, 243374923, 517215283

Offset

1,5

Links

Table of n, a(n) for n=1..33.

Crossrefs

Sequence in context: A352666 A275358 A048008 * A189586 A019498 A237626

Adjacent sequences: A048016 A048017 A048018 * A048020 A048021 A048022

Keyword

nonn

Author

Clark Kimberling

Status

approved