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A318721 Number of strict relatively prime factorizations of n. 10
1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 2, 0, 1, 0, 1, 0, 4, 0, 0, 1, 1, 1, 2, 0, 1, 1, 2, 0, 4, 0, 1, 1, 1, 0, 2, 0, 1, 1, 1, 0, 2, 1, 2, 1, 1, 0, 6, 0, 1, 1, 0, 1, 4, 0, 1, 1, 4, 0, 4, 0, 1, 1, 1, 1, 4, 0, 2, 0, 1, 0, 6, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,24

COMMENTS

a(1) could be either 0 or 1.

LINKS

Table of n, a(n) for n=1..87.

EXAMPLE

The a(60) = 6 factorizations are (3*20), (4*15), (5*12), (2*3*10), (2*5*6), (3*4*5).

MATHEMATICA

strfacs[n_]:=If[n<=1, {{}}, Join@@Table[(Prepend[#1, d]&)/@Select[strfacs[n/d], Min@@#1>d&], {d, Rest[Divisors[n]]}]];

Table[Length[Select[strfacs[n], GCD@@#==1&]], {n, 50}]

CROSSREFS

Cf. A001055, A007716, A045778, A078374, A281116, A317748, A318720.

Sequence in context: A323879 A129308 A159200 * A219201 A331838 A227836

Adjacent sequences:  A318718 A318719 A318720 * A318722 A318723 A318724

KEYWORD

nonn

AUTHOR

Gus Wiseman, Sep 02 2018

STATUS

approved

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Last modified June 5 12:47 EDT 2020. Contains 334840 sequences. (Running on oeis4.)