14335236

Appears in sequences

• Number of permutations tau of {1,...,n} such that k*tau(k) + 1 is prime for every k = 1,...,n.at n=17A321597
• a(n) = 4^n * [x^n] 1/sqrt(1-x) * Product_{k>=1} 1/(1 - x^k).at n=9A325947