Triangle read by rows: T(n, k) = (-8)^k*binomial(2*n, 2*k)*Euler(2*k, 1/2).

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =12a(5) =20a(6) =1a(7) =30a(8) =300a(9) =488a(10) =1a(11) =56a(12) =1400a(13) =13664a(14) =22160a(15) =1a(16) =90a(17) =4200a(18) =102480a(19) =997200a(20) =1616672a(21) =1a(22) =132a(23) =9900a(24) =450912a(25) =10969200a(26) =106700352a(27) =172976960a(28) =1a(29) =182