Number of set partitions of [n] such that all absolute differences between least elements of consecutive blocks are <= three.

A287253

Number of set partitions of [n] such that all absolute differences between least elements of consecutive blocks are <= three.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =51a(6) =191a(7) =780a(8) =3440a(9) =16249a(10) =81736a(11) =435796a(12) =2453100a(13) =14529728a(14) =90294625a(15) =587256087a(16) =3988153356a(17) =28223370977a(18) =207745253237

External references