14634871015domain: NAppears in sequencesRow sums of the triangle A391318, given by T(n,k) = T(n-1,k) + T(n-1,k-1) + T(n-2,k-1) + 1, with T(0,0) = T(n,-1) = T(n,n+1) = 0.at n=26A391272