a(n) = product of sum 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),... . Let N be the sum of all the members of the n-th group. Let k be a member and f(k) = N - k. Then a(n) = the product of all f(k) for k taking all member values.

A080474

a(n) = product of sum 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),... . Let N be the sum of all the members of the n-th group. Let k be a member and f(k) = N - k. Then a(n) = the product of all f(k) for k taking all member values.