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A072504 a(n) = LCM of divisors of n which are <= sqrt(n). 5
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

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.

Cf. A161906, A072499.

Sequence in context: A257977 A070966 A219254 * A072499 A060272 A209315

Adjacent sequences:  A072501 A072502 A072503 * A072505 A072506 A072507

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jul 20 2002

EXTENSIONS

More terms from Matthew Conroy, Sep 09 2002

STATUS

approved

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Last modified November 19 06:03 EST 2019. Contains 329310 sequences. (Running on oeis4.)