A198481 - OEIS

A198481

Square root of the largest square dividing ((2n-1)!)^(2n-3).

1, 1, 240, 304819200, 3440500260470784000, 1827912356210202139164672000000000, 13482302715547740229948201750717130814259200000000000

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OFFSET

1,3

COMMENTS

For the complementary squarefree parts see A197880.

LINKS

FORMULA

a(n) = A000188(A134367(2*n-1)). - R. J. Mathar, Oct 25 2011

MAPLE

A000188 := proc(n)

a := 1 ;

for pf in ifactors(n)[2] do

p := op(1, pf) ;

e := op(2, pf) ;

a := a*p^(floor(e/2)) ;

end do:

a ;

end proc:

A198481 := proc(n)

A000188( A134367(2*n-1)) ;

end proc:

seq(A198481(n), n=1..10) ; # R. J. Mathar, Oct 25 2011

MATHEMATICA

aa = {}; data = Table[kk = Sqrt[(n!)^(n - 2)], {n, 1, 100, 2}]; sp = data /. Sqrt[_] -> 1; sfp = data/sp; sp

Sqrt[#]&/@Table[Max[Select[Divisors[((2n-1)!)^(2n-3)], IntegerQ[Sqrt[#]]&]], {n, 7}] (* Harvey P. Dale, May 24 2024 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

STATUS

approved