1169925120domain: NAppears in sequencesa(n) = sigma(lcm(1,2,...,n)) = A000203(A003418(n)).at n=18A124052a(n) = sigma(lcm(1,2,...,n)) = A000203(A003418(n)).at n=19A124052a(n) = sigma(lcm(1,2,...,n)) = A000203(A003418(n)).at n=20A124052a(n) = sigma(lcm(1,2,...,n)) = A000203(A003418(n)).at n=21A124052