206388domain: NAppears in sequencesIntegers of the form C(2n,n)^2 * Sum_{i=1..n} 1/phi(i).at n=4A066992Matrix inverse of the Narayana triangle A001263.at n=50A103364n+p(n)+p(p(n)) is a square, where p(n) is the n-th prime.at n=29A116011Number of permutations of order n with the length of longest run equal 10.at n=4A230133