A048007 Number of nonempty subsets of {1,2,...,n} in which exactly 2/3 of the elements are <= (n-1)/3.

0, 0, 0, 0, 0, 0, 5, 6, 7, 21, 24, 27, 90, 105, 121, 385, 450, 520, 1651, 1939, 2255, 7175, 8456, 9877, 31416, 37122, 43510, 138510, 164025, 192801, 614019, 728409, 858199, 2734171, 3248322, 3834655, 12220780, 14536951, 17189667

Offset

1,7

Links

Table of n, a(n) for n=1..39.

Crossrefs

Sequence in context: A161925 A078694 A221175 * A273402 A217295 A272676

Adjacent sequences: A048004 A048005 A048006 * A048008 A048009 A048010

Keyword

nonn

Author

Clark Kimberling

Status

approved