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A129649
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Largest order of a permutation of n elements with exactly 4 cycles. Also the largest LCM of a 4-partition of n.
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8
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0, 0, 0, 1, 2, 3, 6, 6, 12, 15, 30, 30, 60, 60, 84, 105, 210, 140, 420, 210, 330, 420, 840, 420, 1260, 1155, 1540, 1365, 2520, 1320, 3080, 3465, 3960, 4095, 5544, 5005, 6930, 6435, 8190, 9009, 10296, 8415, 12870, 11781, 13464, 15015, 18018, 17017, 20592, 21879
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OFFSET
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1,5
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COMMENTS
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a(n) is asymptotic to (n^4)/256.
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LINKS
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EXAMPLE
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a(18)=140 because 18 = 7+5+2+2 and lcm(2,2,5,7) = 140 is maximal.
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MATHEMATICA
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Max[LCM @@@ Compositions[ #, 4]] & /@ Range[1, n] (* needs Combinatorica *)
Join[{0, 0, 0}, Table[Max[LCM@@#&/@IntegerPartitions[n, {4}]], {n, 4, 50}]] (* Harvey P. Dale, Feb 25 2012 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Nickolas Reynolds (nickels(AT)gmail.com), Apr 25 2007
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STATUS
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approved
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