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A189100
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a(n) = lcm(n!,n!')/gcd(n!,n!'), where n!' is the arithmetic derivative of n! (A068311).
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5
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0, 2, 30, 66, 1830, 645, 33180, 198870, 228270, 64785, 7960260, 9738960, 1663226565, 7232635410, 857066210, 1057466410, 307311194190, 767464487790, 278292627277665, 306517823106495, 35302033071305, 147385363695570, 78207294248313230, 198777858520921680
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OFFSET
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1,2
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COMMENTS
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Least common multiple of n! and its arithmetic derivative divided by greatest common divisor of n! and its arithmetic derivative.
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LINKS
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Nathaniel Johnston, Table of n, a(n) for n = 1..200
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FORMULA
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a(n) = lcm(n!,n!')/gcd(n!,n!') = A086130(n!)/A085731(n!) = lcm(A000142(n),A068311(n))/gcd(A000142(n),A068311(n))
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EXAMPLE
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n = 5: 5! = 120, 120' = 244, gcd(120,244) = 4, lcm(120,244) = 7320, 7320/4 = 1830 -> a(5) = 1830.
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CROSSREFS
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A068311, A083346, A083346, A085731, A086130
Sequence in context: A105403 A134644 A244379 * A085637 A193177 A157870
Adjacent sequences: A189097 A189098 A189099 * A189101 A189102 A189103
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KEYWORD
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nonn
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AUTHOR
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Giorgio Balzarotti, Apr 16 2011
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STATUS
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approved
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