Denominator of Bernoulli(2n,1/2).

Terms

a(0) =1a(1) =12a(2) =240a(3) =1344a(4) =3840a(5) =33792a(6) =5591040a(7) =49152a(8) =16711680a(9) =104595456a(10) =173015040a(11) =289406976a(12) =22900899840a(13) =201326592a(14) =116769423360a(17) =51539607552a(19) =824633720832