Bessel polynomial {y_n}''(-1).

Terms

a(0) =0a(1) =0a(2) =6a(3) =-60a(4) =720a(5) =-9870a(6) =153510a(7) =-2679264a(8) =51934680a(9) =-1107917910a(10) =25807660560a(11) =-651977992380