Bernoulli denominators A141056(n), with the exception a(1)=1.

Terms

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