Number of rooted identity trees with 3-colored leaves.

Terms

a(0) =3a(1) =3a(2) =6a(3) =16a(4) =46a(5) =142a(6) =461a(7) =1542a(8) =5278a(9) =18417a(10) =65218a(11) =233816a(12) =846938a(13) =3094943a(14) =11395715a(15) =42237936a(16) =157465847a(17) =590075550a(18) =2221391912a(19) =8397223487a(20) =31861406058a(21) =121300625969a(22) =463233477550