Number of set partitions of [n] such that i-j is a multiple of three for all i,j belonging to the same block.

A275070

Number of set partitions of [n] such that i-j is a multiple of three for all i,j belonging to the same block.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =8a(7) =20a(8) =50a(9) =125a(10) =375a(11) =1125a(12) =3375a(13) =11700a(14) =40560a(15) =140608a(16) =548912a(17) =2142868a(18) =8365427a(19) =36140293a(20) =156133187a(21) =674526133a(22) =3184194060a(23) =15031429200a(24) =70957944000a(25) =362451121200

External references