a(n) = A000203(A344422(n)).

Terms

a(0) =1a(1) =3a(2) =7a(3) =12a(4) =84a(5) =144a(6) =728a(7) =6096a(8) =8736a(9) =19812a(10) =85120a(11) =163520a(12) =738720a(13) =871416a(14) =2419200a(15) =2935296a(16) =7567168a(17) =15193920a(18) =84319872a(19) =169303680a(20) =259445760a(21) =934545248a(22) =8600626944a(23) =9438363648a(24) =19853729280a(25) =34805721600a(26) =87037870374a(27) =165451302016a(28) =254879514624a(29) =957538713600