160629

Appears in sequences

• Numbers k such that sigma(phi(k)) = sigma(k) where sigma is the sum of divisors function A000203 and phi is the Euler totient function A000010.at n=29A033631
• Number of isomers C_n H_{2n} without double bonds.at n=15A036671
• Number of all possible tetrahedra of any size and orientation, formed when intersecting the original regular tetrahedron by planes parallel to its sides and dividing its edges into n equal parts.at n=39A216173