3107640domain: NAppears in sequencesTriangle of generalized Eulerian numbers T(n,k) = <n,k>_2 read by rows, n >= 1, 0 <= k < 2*n.at n=42A269742Number of nonnegative integer n X n matrices with row and column sums 2 and sum of entries below the main diagonal n - 1.at n=6A332729