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A319677
Denominator of A047994(n)/n where A047994 is the unitary totient function.
4
1, 2, 3, 4, 5, 3, 7, 8, 9, 5, 11, 2, 13, 7, 15, 16, 17, 9, 19, 5, 7, 11, 23, 12, 25, 13, 27, 14, 29, 15, 31, 32, 33, 17, 35, 3, 37, 19, 13, 10, 41, 7, 43, 22, 45, 23, 47, 8, 49, 25, 51, 13, 53, 27, 11, 4, 19, 29, 59, 5, 61, 31, 21, 64, 65, 33, 67, 17, 69, 35, 71
OFFSET
1,2
LINKS
FORMULA
a(p) = p, for p prime.
a(A002110(n)) = A060753(n).
a(n) = n / A323409(n) = n / gcd(n, A047994(n)). - Antti Karttunen, Jan 11 2020
MATHEMATICA
uphi[n_] := Product[{p, e} = pe; p^e - 1, {pe, FactorInteger[n]}];
a[n_] := Denominator[uphi[n]/n];
Array[a, 100] (* Jean-François Alcover, Jan 10 2022 *)
PROG
(PARI) a(n)=my(f=factor(n)~); denominator(prod(i=1, #f, f[1, i]^f[2, i]-1)/n);
CROSSREFS
Cf. A047994, A030163, A305678, A319481, A319676 (numerators), A323409, A331177 (ordinal transform).
Sequence in context: A067620 A343253 A330741 * A349634 A294650 A323129
KEYWORD
nonn,frac
AUTHOR
Michel Marcus, Sep 26 2018
STATUS
approved