Triangle T(n,k) = A008297(n,k) + A008297(n,n-k+1), read by rows.

Terms

a(0) =-2a(1) =3a(2) =3a(3) =-7a(4) =-12a(5) =-7a(6) =25a(7) =48a(8) =48a(9) =25a(10) =-121a(11) =-260a(12) =-240a(13) =-260a(14) =-121a(15) =721a(16) =1830a(17) =1500a(18) =1500a(19) =1830a(20) =721a(21) =-5041a(22) =-15162a(23) =-13230a(24) =-8400a(25) =-13230a(26) =-15162a(27) =-5041a(28) =40321a(29) =141176