4th power of rooted tree enumerator: linear forests of 4 rooted trees.

Terms

a(0) =1a(1) =4a(2) =14a(3) =44a(4) =133a(5) =388a(6) =1116a(7) =3168a(8) =8938a(9) =25100a(10) =70334a(11) =196824a(12) =550656a(13) =1540832a(14) =4314190a(15) =12089368a(16) =33911543a(17) =95228760a(18) =267727154a(19) =753579420a(20) =2123637318a(21) =5991571428a(22) =16923929406a(23) =47857425416a(24) =135478757308a(25) =383929643780