205883

Properties

Appears in sequences

• Least prime p such that H(2,n) = sum_{k=1..n}1/k^2 == 0 (mod p) but there is no 0 < k < n with H(2,k) == 0 (mod p), or 1 if such a prime p does not exist.at n=30A242241
• a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 273).at n=12A289603
• Prime numbersat n=18454