a(n) = A118443(n)/(n+1), where A118443 is the row sums of triangle A118441.

Terms

a(0) =1a(1) =-1a(2) =1a(3) =-9a(4) =-31a(5) =79a(6) =161a(7) =-249a(8) =-191a(9) =-481a(10) =-2879a(11) =9111a(12) =22049a(13) =-42641a(14) =-60319a(15) =28071a(16) =-189311a(17) =897599a(18) =2643841a(19) =-6087369a(20) =-11130271a(21) =14084239a(22) =685601a(23) =67678791a(24) =274143169a(25) =-758178721a(26) =-1661999039a(27) =2857102551a(28) =3118415009a(29) =1811852719