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A318504 SumXOR of divisors of n, up to, but not including the second largest of them A032742(n); a(1) = 0 by convention.

%I A318504 #9 Aug 28 2018 15:59:38
%S A318504 0,0,0,1,0,3,0,3,1,3,0,4,0,3,2,7,0,6,0,2,2,3,0,10,1,3,2,0,0,9,0,15,2,
%T A318504 3,4,7,0,3,2,0,0,15,0,12,14,3,0,22,1,12,2,10,0,29,4,6,2,3,0,26,0,3,12,
%U A318504 31,4,27,0,22,2,5,0,5,0,3,8,20,6,17,0,4,11,3,0,14,4,3,2,18,0,3,6,16,2,3,4,46,0,10,0,5,0,53,0,24,26
%N A318504 SumXOR of divisors of n, up to, but not including the second largest of them A032742(n); a(1) = 0 by convention.
%H A318504 Antti Karttunen, <a href="/A318504/b318504.txt">Table of n, a(n) for n = 1..65537</a>
%H A318504 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A318504 a(n) = A032742(n) XOR A227320(n).
%F A318504 For n > 1, a(n) = A106409(n) XOR A178910(n).
%o A318504 (PARI)
%o A318504 A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));
%o A318504 A318504(n) = { my(v=0); fordiv(n,d,if(d<A032742(n), v = bitxor(v,d))); (v); };
%Y A318504 Cf. A003987, A032742, A106409, A178910, A227320, A318505, A318507, A318517.
%K A318504 nonn,base
%O A318504 1,6
%A A318504 _Antti Karttunen_, Aug 28 2018