a(n) = n * A001353(n).

Terms

a(0) =1a(1) =8a(2) =45a(3) =224a(4) =1045a(5) =4680a(6) =20377a(7) =86912a(8) =364905a(9) =1513160a(10) =6211909a(11) =25290720a(12) =102251773a(13) =410963336a(14) =1643288625a(15) =6541692416a(16) =25939798993a(17) =102503274120a(18) =403800061789