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A066574 LCM of numbers <= n and having a factor in common with n. 2
1, 2, 3, 4, 5, 12, 7, 24, 18, 120, 11, 360, 13, 840, 180, 1680, 17, 5040, 19, 5040, 1260, 55440, 23, 55440, 300, 720720, 7560, 720720, 29, 10810800, 31, 1441440, 83160, 24504480, 2100, 73513440, 37, 465585120, 1081080, 2327925600, 41, 1396755360 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
If n is not composite then a(n) = n.
LINKS
EXAMPLE
a(6) = 12 since lcm{ 1,2,3,4,6 } = 12.
MAPLE
A066574 := n -> ilcm(op(select(k->igcd(n, k)<>1, [$1..n]))); seq(A066574(i), i=1..42); # Peter Luschny, Jun 25 2011
MATHEMATICA
f[n_] := Block[{a = 1, k = 2}, While[k < n + 1, If[ GCD[k, n] > 1, a = LCM[a, k]]; k++ ]; Return[a]]; Table[ f[n], {n, 1, 45} ]
CROSSREFS
Sequence in context: A344370 A143482 A193679 * A240304 A325684 A339453
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Dec 19 2001
EXTENSIONS
More terms from Robert G. Wilson v, Dec 26 2001
STATUS
approved

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Last modified March 28 14:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)