Number of partitions of the set {1, 2, 3, ..., 6n+3} into 2n+1 sets of 3 elements each, such that each 3-element set has the same sum (there are no such partitions unless there are 6n+3 elements).

A104185

Number of partitions of the set {1, 2, 3, ..., 6n+3} into 2n+1 sets of 3 elements each, such that each 3-element set has the same sum (there are no such partitions unless there are 6n+3 elements).