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%I #12 Jan 28 2014 09:29:38
%S 1,3,2,7,4,6,6,15,11,12,10,14,12,10,8,31,16,29,18,28,16,30,22,30,29,
%T 20,16,18,28,24,30,63,40,48,32,49,36,54,40,60,40,48,42,54,44,58,46,62,
%U 55,39,32,36,52,48,56,34,40,36,58,56,60,34,38,127,72,120,66,112,80,96,70
%N Binary XOR of divisors of n.
%C If 2^k <= n < 2^(k+1), then also 2^k <= a(n) < 2^(k+1), since any proper divisor of n is < 2^k.
%H Reinhard Zumkeller, <a href="/A178910/b178910.txt">Table of n, a(n) for n = 1..8191</a>
%o (PARI) a(n)=local(ds,r);ds=divisors(n);for(k=1,#ds,r=bitxor(r,ds[k]));r
%o (Haskell)
%o import Data.Bits (xor)
%o a178910 = foldl1 xor . a027750_row :: Integer -> Integer
%o -- _Reinhard Zumkeller_, Nov 17 2012
%Y Cf. A000203, A178908, A178911, A003987.
%Y Cf. A027750, A072594; subsequences A028982 (odd), A028982 (even).
%K base,nonn,look
%O 1,2
%A _Franklin T. Adams-Watters_, Jun 22 2010
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