Powers of rooted tree enumerator.

Terms

a(0) =20a(1) =74a(2) =186a(3) =388a(4) =721a(5) =1236a(6) =1995a(7) =3072a(8) =4554a(9) =6542a(10) =9152a(11) =12516a(12) =16783a(13) =22120a(14) =28713a(15) =36768a(16) =46512a(17) =58194a(18) =72086a(19) =88484a(20) =107709a(21) =130108a(22) =156055a(23) =185952a(24) =220230a(25) =259350a(26) =303804a(27) =354116a(28) =410843a(29) =474576