Denominators in the Maclaurin series for arctan(1+x).

Terms

a(0) =2a(1) =4a(2) =12a(3) =1a(4) =40a(5) =48a(6) =112a(7) =1a(8) =288a(9) =320a(10) =704a(11) =1a(12) =1664a(13) =1792a(14) =3840a(15) =1a(16) =8704a(17) =9216a(18) =19456a(19) =1a(20) =43008a(21) =45056a(22) =94208a(23) =1a(24) =204800a(25) =212992a(26) =442368a(27) =1a(28) =950272a(29) =983040