40220

Appears in sequences

• Numbers k such that the number of primes <= k is phi(phi(k)).at n=23A063999
• Least number 2k such that p^2 divides the numerator of the Bernoulli number B(2k), where p is the n-th irregular prime, A000928(n).at n=9A092681
• Number of unrooted self-avoiding walks with n steps that can make turns from the set +-Pi/7, +-3*Pi/7, +-5*Pi/7.at n=7A306177
• Number of edges in a complete bipartite graph where the vertices in the two parts are placed on opposite sides of a parabola at integer x coordinates |x| = 1, 2, ...n.at n=17A392427