Number of set partitions of [n] such that the difference between each element and its block index is a multiple of three.

A274836

Number of set partitions of [n] such that the difference between each element and its block index is a multiple of three.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =4a(7) =9a(8) =18a(9) =33a(10) =89a(11) =215a(12) =481a(13) =1486a(14) =4187a(15) =10974a(16) =37907a(17) =121114a(18) =362953a(19) =1385575a(20) =4924557a(21) =16494655a(22) =68685792a(23) =268113185a(24) =990074770a(25) =4455129525a(26) =18896355932a(27) =76116156873a(28) =367577989487

External references