55212domain: NAppears in sequencesUsed by Polya in calculating A000598.at n=18A036676Triangle T(n,k), 0 <= k <= n, read by rows, defined by: T(0,0) = 1, T(n,k) = 0 if n<k, T(n,0) = T(n-1,0) + T(n-1,1) and for k >= 1: T(n,k) = T(n-1,k-1) + x*T(n-1,k) + T(n-1,k+1) with x = 3.at n=48A110877