A047198 Number of nonempty subsets of {1,2,...,n} in which exactly 1/5 of the elements are <= n/3.

0, 0, 0, 0, 1, 2, 10, 30, 45, 105, 213, 286, 558, 1110, 1500, 3300, 7435, 10415, 23855, 52871, 73255, 160615, 346745, 476910, 1047438, 2299998, 3181482, 7110522, 15770601, 21851202, 48767082, 107787262, 149093417, 331877557