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a(n) = (a(n-1) OR a(n-2)) XOR n.
0

%I #13 May 21 2021 08:08:10

%S 0,1,3,0,7,2,1,4,13,4,7,12,3,2,13,0,29,12,15,28,11,10,29,8,5,20,15,4,

%T 19,10,5,16,53,20,23,52,19,18,53,16,29,52,23,28,51,18,29,48,13,12,63,

%U 12,11,58,13,8,53,4,15,52,3,10,53,0,117,52,55,116,51,50,117

%N a(n) = (a(n-1) OR a(n-2)) XOR n.

%C Indices of zeros: 2^(2x)-1, e.g. 0, 3, 15, 63, 255.

%F a(0)=0, a(1)=1, a(n) = (a(n-1) OR a(n-2)) XOR n, where OR is the bitwise inclusive-or operator, XOR is the bitwise exclusive-or operator.

%o (Python)

%o prpr = 0

%o prev = 1

%o for n in range(2,77):

%o current = (prev | prpr) ^ n

%o print(prpr, end=',')

%o prpr = prev

%o prev = current

%Y Cf. A182560.

%K nonn,base,easy

%O 0,3

%A _Alex Ratushnyak_, May 06 2012