Expansion of sin(sin(x))*x/2.

Terms

a(0) =0a(1) =1a(2) =-4a(3) =36a(4) =-512a(5) =9360a(6) =-225600a(7) =6935488a(8) =-258670592a(9) =11453942016a(10) =-595273139200