2662569domain: NAppears in sequencesa(n) = 4th elementary symmetric function of first n+3 positive integers congruent to 1 mod 3.at n=5A024214Triangle read by rows: T(n, k) is the Sheffer triangle ((1 - 3*x)^(-1/3), (-1/3)*log(1 - 3*x)). A generalized Stirling1 triangle.at n=50A286718