416641

Appears in sequences

• Strong pseudoprimes to base 15.at n=29A020241
• Pseudoprimes to bases 3 and 5.at n=31A083734
• Overpseudoprimes to base 5.at n=22A141390
• n such that the sum of the factorials of the digits of n equals the sum of d|n, 1<d<n.at n=5A202239
• Octagonal numbers (A000567) that are semiprimes (A001358).at n=34A259677
• Numbers k such that 2^k - 2*k + 1 is prime.at n=35A301744
• The number of regions formed when every pair of n points, placed at the vertices of a regular n-gon, are connected by a circle and where the points lie at the ends of the circle's diameter.at n=40A358782
• Let G_n denote the planar graph defined in A358746 with the addition, if n is odd, of the circle containing the initial n points; sequence gives the number of regions in G_n.at n=41A370976