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URL: https://oeis.org/A072504

⇱ A072504 - OEIS

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A072504
a(n) = LCM of divisors of n which are <= sqrt(n).
6
1, 1, 1, 2, 1, 2, 1, 2, 3, 2, 1, 6, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 5, 2, 3, 4, 1, 30, 1, 4, 3, 2, 5, 12, 1, 2, 3, 20, 1, 6, 1, 4, 15, 2, 1, 12, 7, 10, 3, 4, 1, 6, 5, 28, 3, 2, 1, 60, 1, 2, 21, 8, 5, 6, 1, 4, 3, 70, 1, 24, 1, 2, 15, 4, 7, 6, 1, 40, 9, 2, 1, 84, 5, 2, 3, 8, 1, 90, 7, 4, 3, 2, 5, 24
OFFSET
1,4
LINKS
EXAMPLE
a(20) = 4: the divisors of 20 are 1,2,4,5,10 and 20; a(20) = lcm(1,2,4) = 4.
MAPLE
A072504 := proc(n)
local ds ;
ds := [] ;
for d in numtheory[divisors](n) do
if d^2 <= n then
ds := [op(ds), d] ;
end if;
end do:
ilcm(op(ds)) ;
end proc:
seq(A072504(n), n=1..20) ; # R. J. Mathar, Oct 03 2014
MATHEMATICA
Table[LCM@@Select[Divisors[n], #<=Sqrt[n]&], {n, 100}] (* Harvey P. Dale, Aug 26 2014 *)
PROG
(Haskell)
a072504 = foldl1 lcm . a161906_row -- Reinhard Zumkeller, Mar 08 2013
CROSSREFS
Cf. A072505.
Sequence in context: A219254 A382486 A372833 * A072499 A060272 A209315
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Jul 20 2002
EXTENSIONS
More terms from Matthew Conroy, Sep 09 2002
STATUS
approved