The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A189100 a(n) = lcm(n!,n!')/gcd(n!,n!'), where n!' is the arithmetic derivative of n! (A068311). 5
 0, 2, 30, 66, 1830, 645, 33180, 198870, 228270, 64785, 7960260, 9738960, 1663226565, 7232635410, 857066210, 1057466410, 307311194190, 767464487790, 278292627277665, 306517823106495, 35302033071305, 147385363695570, 78207294248313230, 198777858520921680 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Least common multiple of n! and its arithmetic derivative divided by greatest common divisor of n! and its arithmetic derivative. LINKS Nathaniel Johnston, Table of n, a(n) for n = 1..200 FORMULA a(n) = lcm(n!,n!')/gcd(n!,n!') = A086130(n!)/A085731(n!) = lcm(A000142(n),A068311(n))/gcd(A000142(n),A068311(n)) EXAMPLE n = 5: 5! = 120, 120' = 244, gcd(120,244) = 4, lcm(120,244) = 7320, 7320/4 = 1830 -> a(5) = 1830. CROSSREFS Sequence in context: A105403 A134644 A244379 * A085637 A193177 A157870 Adjacent sequences: A189097 A189098 A189099 * A189101 A189102 A189103 KEYWORD nonn AUTHOR Giorgio Balzarotti, Apr 16 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 8 23:03 EST 2023. Contains 360153 sequences. (Running on oeis4.)