327440609domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = 6*b_6(n)+5, where b_6 lists the indices of zeros of the sequence A261306: u(n) = abs(u(n-1)-gcd(u(n-1),6*n-1)), u(1) = 1.at n=9A186258Prime numbersat n=17654849