A048074 Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n+2)/3.

0, 0, 0, 0, 2, 8, 12, 30, 63, 86, 182, 392, 560, 1270, 2800, 4070, 9020, 19595, 28679, 63518, 138866, 205478, 455966, 997640, 1485624, 3290520, 7201692, 10782222, 23878212, 52311408, 78678468, 174179258, 381766253, 576312440