OFFSET
1,1
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
a^d == 1 mod q
EXAMPLE
18^3 == 1 mod 49
MAPLE
filter:= proc(n)
if isprime(n) then return false fi;
igcd((n-1)/2^padic:-ordp(n-1, 2), numtheory:-phi(n)) > 1
end proc:
select(filter, [seq(i, i=9..2000, 2)]); # Robert Israel, Dec 20 2017
MATHEMATICA
filterQ[n_] := If[PrimeQ[n], False, GCD[(n-1)/2^IntegerExponent[n-1, 2], EulerPhi[n]] > 1];
Select[Range[9, 2000, 2], filterQ] (* Jean-François Alcover, Sep 25 2020, after Robert Israel *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Karsten Meyer, Dec 26 2010
EXTENSIONS
Corrected by Robert Israel, Dec 20 2017
STATUS
approved