22802028

Appears in sequences

• Number of ways to arrange integers 1 through n so that the sum of each adjacent pair is prime, not counting reversals.at n=18A051239
• Number of ways of writing the numbers 1 .. n in a sequence so that the sum of any two adjacent numbers is a prime; reversing the sequence does not count as different.at n=18A064821
• 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=18A073452