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 A348001 #9 Sep 25 2021 04:45:24 %S A348001 1,1,2,2,2,2,2,2,2,2,2,4,2,2,4,2,2,2,2,4,4,2,2,4,2,2,2,4,2,4,2,2,4,2, %T A348001 4,4,2,2,4,4,2,4,2,4,4,2,2,4,2,2,4,4,2,2,4,4,4,2,2,8,2,2,4,2,4,4,2,4, %U A348001 4,4,2,4,2,2,4,4,4,4,2,4,2,2,2,7,4,2,4 %N A348001 Number of distinct values obtained when the unitary totient function (A047994) is applied to the unitary divisors of n. %H A348001 Amiram Eldar, <a href="/A348001/b348001.txt">Table of n, a(n) for n = 1..10000</a> %F A348001 a(2^e) = 2 for e > 1. %F A348001 a(p^e) = 2 for an odd prime p and e > 0. %F A348001 a(n) >= omega(n), with equality if and only if n is in A278568. %e A348001 n = 6 has four unitary divisors: 1, 2, 3 and 6. Applying A047994 to these gives 1, 1, 2 and 2, with just 2 distinct values, thus a(6) = 2. %e A348001 n = 12 has four unitary divisors: 1, 3, 4 and 12. Applying A047994 to these gives 4 distinct values, 1, 2, 3 and 6, thus a(12) = 4. %t A348001 f[p_, e_] := p^e - 1; uphi[1] = 1; uphi[n_] := Times @@ f @@@ FactorInteger[n]; a[n_] := Length @ Union[uphi /@ Select[Divisors[n], CoprimeQ[#, n/#] &]]; Array[a,100] %Y A348001 The unitary version of A319696. %Y A348001 Cf. A047994, A077610, A278568. %K A348001 nonn %O A348001 1,3 %A A348001 _Amiram Eldar_, Sep 23 2021