A322352 - OEIS

%I #10 Dec 05 2018 17:24:17

%S 1,1,2,2,4,2,6,4,3,4,10,2,12,6,8,8,16,3,18,4,12,10,22,4,5,12,9,6,28,8,

%T 30,16,20,16,24,6,36,18,24,4,40,12,42,10,8,22,46,8,7,5,32,12,52,9,40,

%U 6,36,28,58,8,60,30,12,32,48,20,66,16,44,24,70,12,72,36,8,18,60,24,78,8,27,40,82,12,64,42,56,10,88,8

%N a(n) = max(A003557(n), A173557(n)).

%H Antti Karttunen, <a href="/A322352/b322352.txt">Table of n, a(n) for n = 1..16384</a>

%F a(n) = max(A003557(n), A173557(n)).

%F a(n) = A000010(n) / A322351(n).

%t a[n_] := If[n == 1, 1, Module[{f=FactorInteger[n]}, Max[ Times @@ (First[#]^ (Last[#]-1)& /@  f), Times@@((#-1)& @@@ f)]]]; Array[a, 120] (* _Amiram Eldar_, Dec 05 2018 *)

%o (PARI)

%o A003557(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); }; \\ From A003557

%o A173557(n) = factorback(apply(p -> p-1, factor(n)[, 1]));

%o A322352(n) = max(A003557(n), A173557(n));

%Y Cf. A000010, A003557, A173557, A322320, A322321, A322351, A322355.

%K nonn

%O 1,3

%A _Antti Karttunen_, Dec 05 2018