279349domain: NAppears in sequencesTriangle T(n,k) of number of chains of length k in partitions of an n-set ordered by refinement.at n=32A331955a(n) = coefficient of x^n in A(x) = Sum_{n>=0} x^n*F(x)^n * (1 - x^n*F(x)^n)^n, where F(x) = 1 + x*F(x)^3 is a g.f. of A001764.at n=10A357793