321052999680domain: NAppears in sequencesFor n > 2 , a(n) = a(n-2) + lcm(a(n-2), n-1) with a(1)=2, a(2)=2.at n=27A217662Numerator of Product_{k=1..n-1} (1 + 1/prime(k)).at n=13A236435