1681732464

Appears in sequences

• 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).at n=6A080473
• Seventh right hand column of triangle A165674.at n=21A165679
• a(n) = (4*n)!/(3*n)! * Sum_{k=1..n} 1/(3*n+k).at n=6A384137