64540

Appears in sequences

• Number of series-reduced rooted trees with n nodes.at n=21A001679
• Number of lines through exactly 3 points of an n X n grid of points.at n=39A018810
• a(n) is smallest number m such that m = n*pi(m), where pi(k) = number of primes <= k (A000720).at n=8A038625
• Numbers k such that pi(k) divides k.at n=38A057809
• Consider the sequence {b(m)} of nonprimes; sequence gives values of m where gcd{m, b(m)} increases.at n=38A058011
• Number of homeomorphically irreducible rooted trees (also known as series-reduced rooted trees, or rooted trees without nodes of degree 2) with n >= 1 nodes.at n=21A059123
• Consecutive min and max-terms of solution-clusters of A057809, i,e, least and largest solutions to n=x/A000720[x].at n=16A087241
• Numbers k such that k and k^2 use only the digits 0, 1, 4, 5 and 6.at n=20A136855
• Numbers n such that pi(n) = (1/10)*n.at n=0A165689