cp's OEIS Frontend

A336647 a(n) = n - A336566(n).

%I A336647 #14 Jul 31 2020 12:36:44
%S A336647 0,1,1,3,1,6,1,7,8,8,1,10,1,10,9,15,1,15,1,18,11,14,1,18,24,16,25,14,
%T A336647 1,18,1,31,15,20,13,35,1,22,17,30,1,30,1,42,42,26,1,34,48,49,21,50,1,
%U A336647 42,17,54,23,32,1,54,1,34,62,63,19,54,1,66,27,66,1,69,1,40,74,74,19,66,1,78,80,44,1,70,23,46,33,86
%N A336647 a(n) = n - A336566(n).
%C A336647 Some terms, for example a(600) and a(6552), are negative. - _Georg Fischer_, Jul 31 2020
%H A336647 Antti Karttunen, <a href="/A336647/b336647.txt">Table of n, a(n) for n = 1..16384</a>
%H A336647 Antti Karttunen, <a href="/A336647/a336647.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%F A336647 a(n) = n - A336566(n).
%o A336647 (PARI)
%o A336647 A007947(n) = factorback(factorint(n)[, 1]);
%o A336647 A057723(n) = { my(r=A007947(n)); (r*sigma(n/r)); };
%o A336647 A308135(n) = (sigma(n)-A057723(n));
%o A336647 A336563(n) = (A057723(n)-n);
%o A336647 A336564(n) = (n - A308135(n));
%o A336647 A336566(n) = gcd(A336563(n), A336564(n));
%o A336647 A336647(n) = (n - A336566(n));
%Y A336647 Cf. A000203, A007947, A057723, A308135, A336563, A336564, A336566.
%Y A336647 Cf. A336555 (positions where differs from A336646).
%Y A336647 Cf. A336565 (positions where a(n) = 2*n - A057723(n) = n - A336563(n)).
%Y A336647 Cf. also A336645.
%K A336647 sign
%O A336647 1,4
%A A336647 _Antti Karttunen_, Jul 30 2020