A048066 Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-4)/2.

0, 0, 0, 0, 0, 0, 0, 20, 35, 105, 168, 364, 588, 1260, 2250, 4960, 9460, 20020, 38500, 77001, 148161, 286689, 560469, 1071525, 2143051, 4064071, 8259196, 15473436, 31705476, 58620692, 120894085, 221227279, 459855214

Offset

1,8

Links

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

Crossrefs

Sequence in context: A254363 A229356 A384493 * A287055 A326403 A335251

Adjacent sequences: A048063 A048064 A048065 * A048067 A048068 A048069

Keyword

nonn

Author

Clark Kimberling

Status

approved