Fourth convolution of A107841.

Terms

a(0) =1a(1) =8a(2) =64a(3) =520a(4) =4304a(5) =36232a(6) =309504a(7) =2677128a(8) =23405520a(9) =206522888a(10) =1836913216a(11) =16452907016a(12) =148274884688