A166140 Product of the nonzero elements of the n-th row of A166139.

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

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: A015052 A348036 A053166 * A019555 A378997 A243074

Adjacent sequences: A166137 A166138 A166139 * A166141 A166142 A166143

Keyword

nonn

Author

Mats Granvik, Oct 08 2009

Status

approved