161394domain: NAppears in sequencesSquare array A(n,k), n > 0, k > 0, read by downward antidiagonals: A(n,k) is the number of columns in all k-compositions of n.at n=49A382818Numbers that can be represented as p^r + q^s with 4 distinct odd primes p, q, r, s.at n=21A390179