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A344870 Number of distinct prime factors of n^n-1.

%I A344870 #24 Jul 04 2024 03:35:09
%S A344870 1,2,3,3,4,4,6,6,5,4,8,5,5,7,7,4,8,3,11,9,8,6,12,11,8,9,11,9,14,4,12,
%T A344870 8,13,10,18,9,8,10,15,7,16,6,14,17,8,5,18,17,13,14,17,7,15,10,18,8,10,
%U A344870 5,26,7,9,14,19,14,17,9,15,11,19,7,29,12,7,11,19,12,21,8,22,25,6,6,26,16,9,15,21,8,26,11,15,13,11,11,25,8,12,14,26
%N A344870 Number of distinct prime factors of n^n-1.
%H A344870 Amiram Eldar, <a href="/A344870/b344870.txt">Table of n, a(n) for n = 2..138</a>
%H A344870 factordb, <a href="http://factordb.com/index.php?query=n%5En-1&amp;use=n&amp;perpage=20&amp;format=1&amp;sent=1&amp;PR=1&amp;PRP=1&amp;C=1&amp;CF=1&amp;U=1&amp;FF=1&amp;VP=1&amp;EV=1&amp;OD=1&amp;VC=1&amp;n=80">Factors of n^n-1</a>.
%F A344870 a(n) = A001221(A048861(n)).
%t A344870 a[n_] := PrimeNu[n^n - 1]; Array[a, 45, 2] (* _Amiram Eldar_, Jun 01 2021 *)
%o A344870 (PARI) a(n) = omega(n^n-1);
%o A344870 (Magma) [#PrimeDivisors(n^n-1): n in [2..100]];
%Y A344870 Cf. A001221, A048861, A309941, A334167, A344869.
%K A344870 nonn
%O A344870 2,2
%A A344870 _Seiichi Manyama_, May 31 2021