Number of n-member subsets of [3*n] whose elements sum to a multiple of three.

A318591

Number of n-member subsets of [3*n] whose elements sum to a multiple of three.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =30a(4) =165a(5) =1001a(6) =6198a(7) =38760a(8) =245157a(9) =1562331a(10) =10015005a(11) =64512240a(12) =417226230a(13) =2707475148a(14) =17620076360a(15) =114955810530a(16) =751616304549

External references