134953

Appears in sequences

• Triangular array read by rows: T(n,k) is the number of f:{1,2,...,n}->{1,2,...,n} with exactly 2k elements that have a preimage of even (possibly zero) cardinality; n>=0, 0<=k<=floor(n/2).at n=19A225942
• a(n) = 1680*n^4 - 168*n^2 + 128*n + 1.at n=3A272127