A072504 a(n) = LCM of divisors of n which are <= sqrt(n).

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

Author

Amarnath Murthy, Jul 20 2002

Keywords

• nonn

Examples

			a(20) = 4: the divisors of 20 are 1,2,4,5,10 and 20; a(20) = lcm(1,2,4) = 4.
		

Links

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

Crossrefs

Cf. A072505.

Cf. A161906, A072499.

Programs

Haskell

a072504 = foldl1 lcm . a161906_row  -- Reinhard Zumkeller, Mar 08 2013

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 *)

Extensions

More terms from Matthew Conroy, Sep 09 2002