67408

Appears in sequences

• Alkane (or paraffin) numbers l(9,n).at n=18A018210
• Triangle read by rows: T(n,k) is the number of derangements of {1,2,...,n} having genus k (see first comment for definition of genus).at n=39A178514
• Array read by downward antidiagonals: A(n,k) = A(n-1,k+1) + 2*(k+1)!*Sum_{j=0..k} A(n-1,j)/j! with A(0,k) = 2*(k+1)!, n >= 0, k >= 0.at n=19A379459