Denominator of Sum_{k=1..n} 1/(n+k).

Terms

a(0) =2a(1) =12a(2) =60a(3) =840a(4) =2520a(5) =27720a(6) =360360a(7) =144144a(8) =2450448a(9) =232792560a(10) =232792560a(11) =5354228880a(12) =26771144400a(13) =11473347600a(14) =332727080400