64700

Appears in sequences

• Numbers k such that pi(k) divides k.at n=44A057809
• Consider the sequence {b(m)} of nonprimes; sequence gives values of m where gcd{m, b(m)} increases.at n=44A058011
• Numbers k such that the value pi(k), the number of primes <= k, can be obtained deleting some of the repeating adjacent digits of k.at n=20A113898
• a(1) = 1, a(2) = 2; for n > 1, a(n) = sum of the next two smallest integers > a(n-1) which are coprime to the sum s = a(1) + ... + a(n-1).at n=14A131357
• Numbers n such that pi(n) = (1/10)*n.at n=6A165689
• Number of nX3 -1,1 arrays such that the sum over i=1..n,j=1..3 of i*x(i,j) is zero and rows are nondecreasing (ways to put 3 thrusters pointing east or west at each of n positions 1..n distance from the hinge of a south-pointing gate without turning the gate).at n=10A225304
• 30-gonal pyramidal numbers: a(n) = n*(n+1)*(28*n-25)/6.at n=24A256650
• Number of n-vertex, 2-edge multigraphs that are not nesting. Number of n-vertex, 2-edge multigraphs that are not crossing.at n=25A326278
• a(n) = Sum_{k=1..n} tan(k*Pi/(1+2*n))^4.at n=12A377858
• Numbers k such that pi(k) = rad(k), where pi = A000720, rad = A007947.at n=4A378928