A189100 a(n) = lcm(n!,n!')/gcd(n!,n!'), where n!' is the arithmetic derivative of n! (A068311).

0, 2, 30, 66, 1830, 645, 33180, 198870, 228270, 64785, 7960260, 9738960, 1663226565, 7232635410, 857066210, 1057466410, 307311194190, 767464487790, 278292627277665, 306517823106495, 35302033071305, 147385363695570, 78207294248313230, 198777858520921680

Offset: 1

Author

Giorgio Balzarotti, Apr 16 2011

Keywords

• nonn

Comments

Least common multiple of n! and its arithmetic derivative divided by greatest common divisor of n! and its arithmetic derivative.

Examples

			n = 5: 5! = 120, 120' = 244, gcd(120,244) = 4, lcm(120,244) = 7320, 7320/4 = 1830 -> a(5) = 1830.
		

Links

• Nathaniel Johnston, Table of n, a(n) for n = 1..200

Crossrefs

A068311, A083346, A083346, A085731, A086130

Formula

a(n) = lcm(n!,n!')/gcd(n!,n!') = A086130(n!)/A085731(n!) = lcm(A000142(n),A068311(n))/gcd(A000142(n),A068311(n))