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A166140 Product of the nonzero elements of the n-th row of A166139. 3
1, 2, 3, 2, 5, 6, 7, 2, 3, 10, 11, 6, 13, 14, 15, 2, 17, 6, 19, 10, 21, 22, 23, 6, 5, 26, 3, 14, 29, 900, 31, 2, 33, 34, 35, 6, 37, 38, 39, 10, 41, 1764, 43, 22, 15, 46, 47, 6, 7, 10, 51, 26, 53, 6, 55, 14, 57, 58, 59, 900, 61, 62, 21, 2, 65, 4356, 67, 34, 69, 4900, 71, 6, 73, 74, 15 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Differs from A007947 at n = 30.

LINKS

Table of n, a(n) for n=1..75.

MAPLE

A080305 := proc(n) if numtheory[mobius](n) < 0 then n; else 1; end if; end proc:

A126988 := proc(n, k) if n mod k = 0  then n/k ; else 0; end if; end proc:

A166139 := proc(n, k) A080305(A126988(n, k)) ; end proc:

A166140 := proc(n) a := 1 ; for k from 1 to n do if n mod k = 0 then a := a* A166139(n, k) ; end if; end do: a ; end proc:

seq(A166140(n), n=1..75) ; # R. J. Mathar, May 30 2011

MATHEMATICA

A080305[n_]:= If[MoebiusMu[n]<0, n, 1];

A126988[n_, k_]:=If[Mod[n, k]==0, n/k, 0];

A166139[n_, k_]:=A080305[A126988[n, k]];

A166140[n_]:= (p=1; For[k=1, k<n, k++, If[Mod[n, k]==0, p*=A166139[n, k]]]; p)

Table[A166140[n], {n, 100}] (* Jon Maiga, Jan 10 2019 *)

CROSSREFS

Cf. A166139, A014963.

Sequence in context: A062953 A015052 A053166 * A019555 A243074 A304776

Adjacent sequences:  A166137 A166138 A166139 * A166141 A166142 A166143

KEYWORD

nonn

AUTHOR

Mats Granvik, Oct 08 2009

STATUS

approved

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Last modified May 7 20:36 EDT 2021. Contains 343652 sequences. (Running on oeis4.)