RosettaCodeData/Task/M-bius-function/Jq/m-bius-function-4.jq

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def isSquareFree:
. as $n
| 2
| until ( (. * . > $n) or . == 0;
if ($n % (.*.) == 0) then 0 # i.e. stop
elif . > 2 then . + 2
else . + 1
end )
| . != 0;
def mu:
. as $n
| if . < 1 then "Argument to mu must be a positive integer" | error
elif . == 1 then 1
else if isSquareFree
then if ((prime_factors|length) % 2 == 0) then 1
else -1
end
else 0
end
end;