a(n) = sum of the products of taking n-1 numbers from the next n numbers. The next n numbers can be grouped like this (1), (2,3), (4,5,6), (7,8,9,10),... and a(n) is the (sum of the reciprocals of all members) multiplied by (the product of all members).

A080473

a(n) = sum of the products of taking n-1 numbers from the next n numbers. The next n numbers can be grouped like this (1), (2,3), (4,5,6), (7,8,9,10),... and a(n) is the (sum of the reciprocals of all members) multiplied by (the product of all members).