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a(n) = Sum_{d|n, d < n/d} (d XOR n/d), where XOR is bitwise-xor (A003987).
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%I #14 Jan 25 2024 12:25:38

%S 0,3,2,5,4,8,6,15,8,18,10,24,12,20,20,27,16,35,18,30,24,32,22,52,24,

%T 42,36,44,28,56,30,63,40,54,36,81,36,56,52,90,40,80,42,80,68,68,46,

%U 116,48,93,68,86,52,112,68,112,72,90,58,144,60,92,98,119,72,136,66,122,88,128,70,171,72,114,110,136,88,152,78

%N a(n) = Sum_{d|n, d < n/d} (d XOR n/d), where XOR is bitwise-xor (A003987).

%H Antti Karttunen, <a href="/A318460/b318460.txt">Table of n, a(n) for n = 1..16384</a>

%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%F a(n) = (1/2) * Sum_{d|n} (d XOR n/d).

%F a(n) = A318462(n) - A037213(n).

%o (PARI) A318460(n) = { my(xors=0); fordiv(n,d, if(d<(n/d), xors += bitxor(d,n/d))); (xors); };

%Y Cf. A003987, A037213, A318461, A318462, A318463.

%K nonn,base

%O 1,2

%A _Antti Karttunen_, Aug 28 2018