cp's OEIS Frontend

A318508 a(n) = A032742(n) AND A001065(n)-A032742(n), where AND is bitwise-and (A004198) and A001065 = sum of proper divisors and A032742 = the largest proper divisor of n.

%I A318508 #6 Aug 28 2018 15:59:12
%S A318508 0,0,0,0,0,3,0,0,1,1,0,2,0,3,4,0,0,8,0,8,4,3,0,8,1,1,0,14,0,11,0,0,0,
%T A318508 1,6,0,0,3,4,20,0,1,0,18,2,3,0,16,1,16,0,16,0,3,2,4,0,1,0,14,0,3,20,0,
%U A318508 4,33,0,0,4,35,0,4,0,1,24,2,8,35,0,0,9,1,0,34,0,3,4,32,0,33,8,14,4,3,2,32,0,16,0,2,0,51,0,52,32
%N A318508 a(n) = A032742(n) AND A001065(n)-A032742(n), where AND is bitwise-and (A004198) and A001065 = sum of proper divisors and A032742 = the largest proper divisor of n.
%H A318508 Antti Karttunen, <a href="/A318508/b318508.txt">Table of n, a(n) for n = 1..65537</a>
%H A318508 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A318508 a(n) = A004198(A032742(n), A318505(n)).
%F A318508 For n > 1, a(n) = A001065(n) - A318506(n) = (A001065(n) - A318507(n))/2.
%o A318508 (PARI)
%o A318508 A001065(n) = (sigma(n)-n);
%o A318508 A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));
%o A318508 A318505(n) = if(1==n,0,A001065(n)-A032742(n));
%o A318508 A318508(n) = bitand(A318505(n),A032742(n));
%Y A318508 Cf. A001065, A004198, A032742, A318505, A318506, A318507.
%Y A318508 Cf. also A318457, A318517.
%K A318508 nonn,base
%O A318508 1,6
%A A318508 _Antti Karttunen_, Aug 28 2018