Partial sums of A058681.

Terms

a(0) =1a(1) =8a(2) =44a(3) =215a(4) =1028a(5) =5040a(6) =25931a(7) =141394a(8) =818940a(9) =5030489a(10) =32670830a(11) =223561960a(12) =1606504121a(13) =12086613500a(14) =94951417768a(15) =777028092855