A047188 Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-2)/2.

0, 0, 0, 0, 0, 4, 10, 30, 60, 121, 217, 385, 700, 1260, 2521, 4711, 9940, 18340, 38500, 68772, 142833, 250185, 523965, 914485, 1950949, 3405402, 7357416, 12788516, 27747356, 47902764, 104171886, 178864378, 390678883, 668688388

Offset

1,6

Links

Table of n, a(n) for n=1..34.

Crossrefs

Sequence in context: A344203 A330529 A048044 * A002220 A222807 A090578

Adjacent sequences: A047185 A047186 A047187 * A047189 A047190 A047191

Keyword

nonn

Author

Clark Kimberling

Status

approved