452136

Appears in sequences

• a(n) is the number of essentially different ways in which the integers 1,2,3,...,n can be arranged in a sequence such that all pairs of adjacent integers sum to a prime number. Rotations and reversals are counted only once.at n=15A073452
• Number of regular tetrahedra in an n-node-per-edge tetrahedral grid.at n=40A269747