a(n) = denominator(Sum_{j=0..n} Bernoulli(j, 1) * Bernoulli(n - j, 1)).

Terms

a(0) =1a(1) =1a(2) =12a(3) =6a(4) =180a(5) =30a(6) =630a(7) =42a(8) =2100a(9) =30a(10) =3465a(11) =66a(12) =6306300a(13) =2730a(14) =30030a(15) =6a(16) =2187900a(17) =510a(18) =101846745a(19) =798a(20) =355655300a(21) =330a(22) =133855722a(23) =138a(24) =121808707020a(25) =2730a(26) =10140585a(27) =6a(28) =194090796900a(29) =870