258017

Appears in sequences

• Let v = list of denominators of Farey series of order n (see A006843); let b(n) = Sum k*k'/(k+k'), where (k,k') are pairs of successive terms of v; a(n) = numerator of b(n).at n=6A278052
• Numbers k > 2 such that 3^(k-1) == 1 (mod k) and gcd(k, 2^(k-1)-1) = 1.at n=8A306144
• Odd numbers k > 1 such that gcd(3,k) = 1 and 3^((k-1)/2) == -(3/k) (mod k), where (3/k) is the Jacobi symbol (or Kronecker symbol); Euler pseudoprimes to base 3 (A262051) that are not Euler-Jacobi pseudoprimes to base 3 (A048950).at n=10A375490