Third column of A008296.

Terms

a(0) =1a(1) =6a(2) =5a(3) =-15a(4) =49a(5) =-196a(6) =944a(7) =-5340a(8) =34716a(9) =-254760a(10) =2078856a(11) =-18620784a(12) =180973584a(13) =-1887504768a(14) =20887922304a(15) =-242111586816