5309441domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = (a(n-1) * a(n-3) - (-1)^n * a(n-2)^2) / a(n-4) with a(0) = 0, a(1) = ... = a(4) = 1.at n=21A247368Prime numbersat n=368521