A340081 - OEIS

%I #7 Dec 28 2020 17:47:59

%S 1,1,2,1,4,1,6,1,4,1,10,1,12,1,2,1,16,1,18,1,4,1,22,1,8,1,2,3,28,1,30,

%T 1,4,1,2,1,36,1,2,1,40,1,42,1,4,1,46,1,12,1,2,3,52,1,2,1,4,1,58,1,60,

%U 1,2,1,16,5,66,1,4,3,70,1,72,1,2,3,4,1,78,1,16,1,82,1,4,1,2,1,88,1,18,1,4,1,2,1,96,1,2,1,100

%N a(n) = gcd(n-1, A003958(n)).

%H Antti Karttunen, <a href="/A340081/b340081.txt">Table of n, a(n) for n = 1..16384</a>

%H Antti Karttunen, <a href="/A340081/a340081.txt">Data supplement: n, a(n) computed for n = 1..65537</a>

%F a(n) = gcd(n-1, A003958(n)).

%F a(n) = A003958(n) / A340082(n).

%F For n > 1, a(n) = (n-1) / A340083(n).

%o (PARI)

%o A003958(n) = if(1==n,n,my(f=factor(n)); for(i=1,#f~,f[i,1]--); factorback(f));

%o A340081(n) = gcd(n-1, A003958(n));

%Y Cf. A003958, A340082, A340083.

%Y Cf. also A049559, A340071.

%K nonn

%O 1,3

%A _Antti Karttunen_, Dec 28 2020