Number of bicolored trees on n unlabeled nodes such that black nodes are not adjacent to each other and every white node is adjacent to a black node.

A339837

Number of bicolored trees on n unlabeled nodes such that black nodes are not adjacent to each other and every white node is adjacent to a black node.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =18a(7) =44a(8) =111a(9) =296a(10) =819a(11) =2332a(12) =6808a(13) =20302a(14) =61559a(15) =189413a(16) =590091a(17) =1858187a(18) =5906637a(19) =18932016a(20) =61130413a(21) =198697205a(22) =649706622a(23) =2135958254a(24) =7056831766a(25) =23420011178a(26) =78048740454a(27) =261099605923a(28) =876564670090

External references