Number of set partitions of [n] such that no part contains two elements with a circular distance less than three.

A261478

Number of set partitions of [n] such that no part contains two elements with a circular distance less than three.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =8a(7) =29a(8) =106a(9) =491a(10) =2449a(11) =12860a(12) =72488a(13) =435241a(14) =2763053a(15) =18485280a(16) =129916333a(17) =956237591a(18) =7351602714a(19) =58897588844a(20) =490680801682

External references