Expansion of d/dx arctan(x*A001003(x)).

Terms

a(0) =1a(1) =2a(2) =8a(3) =40a(4) =206a(5) =1084a(6) =5802a(7) =31440a(8) =171946a(9) =947132a(10) =5247010a(11) =29203928a(12) =163176586a(13) =914744612a(14) =5142354178a(15) =28978786976a(16) =163652047834a(17) =925925993132