Denominator of Bernoulli number B_n.

Terms

a(0) =1a(1) =2a(2) =6a(3) =1a(4) =30a(5) =1a(6) =42a(7) =1a(8) =30a(9) =1a(10) =66a(11) =1a(12) =2730a(13) =1a(14) =6a(15) =1a(16) =510a(17) =1a(18) =798a(19) =1a(20) =330a(21) =1a(22) =138a(23) =1a(24) =2730a(25) =1a(26) =6a(27) =1a(28) =870a(29) =1