Problem #68
A Mixture of Ryski's Problems
Ryski was asked compute the sum of the series
\sum\limits_{k=0}^{∞}(1/((4k + 1)(4k + 2)(4k + 3)(4k + 4))).
Let this summation be p.
Ryski also has 2*n different pens (n ∈ N, n ≥ 2). Each day, he takes n pens with him to school. After some days the following condition was fulfilled: every two pens were together on at least one day. Let the minimum number of days needed for this to happen be q.
Give the answer as [p * q * {10^{20}}], where [x] denotes the greatest integer less than or equal to x.