35819033domain: NPropertiesPrimalityPrimeyesAppears in sequencesLet v = list of denominators of Farey series of order n (see A006843); let b(n) = Sum 1/(k*k'*(k+k')), where (k,k') are pairs of successive terms of v; a(n) = numerator of b(n).at n=13A278047Prime numbersat n=2193882