This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A319677 #15 Jan 10 2022 06:33:58
%S A319677 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,
%T A319677 29,15,31,32,33,17,35,3,37,19,13,10,41,7,43,22,45,23,47,8,49,25,51,13,
%U A319677 53,27,11,4,19,29,59,5,61,31,21,64,65,33,67,17,69,35,71
%N A319677 Denominator of A047994(n)/n where A047994 is the unitary totient function.
%H A319677 Antti Karttunen, <a href="/A319677/b319677.txt">Table of n, a(n) for n = 1..20000</a>
%F A319677 a(p) = p, for p prime.
%F A319677 a(A002110(n)) = A060753(n).
%F A319677 a(n) = n / A323409(n) = n / gcd(n, A047994(n)). - _Antti Karttunen_, Jan 11 2020
%t A319677 uphi[n_] := Product[{p, e} = pe; p^e - 1, {pe, FactorInteger[n]}];
%t A319677 a[n_] := Denominator[uphi[n]/n];
%t A319677 Array[a, 100] (* _Jean-François Alcover_, Jan 10 2022 *)
%o A319677 (PARI) a(n)=my(f=factor(n)~); denominator(prod(i=1, #f, f[1, i]^f[2, i]-1)/n);
%Y A319677 Cf. A047994, A030163, A305678, A319481, A319676 (numerators), A323409, A331177 (ordinal transform).
%Y A319677 Cf. A002110, A060753.
%K A319677 nonn,frac
%O A319677 1,2
%A A319677 _Michel Marcus_, Sep 26 2018