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%I #5 May 04 2012 12:50:15
%S 0,1,3,1,8,14,16,37,61,89,144,244,392,633,1023,1641,2680,4306,6968,
%T 11261,18209,29489,47688,77200,124880,202073,326931,528993,855952,
%U 1384942,2240896,3625869,5866797,9492633,15359464,24852068,40211496,65063537,105275007
%N a(0)=0, a(1)=1, a(n)=(a(n-1) XOR n) + a(n-2).
%C Terms with indices 6k+1, 6k+2, 6k+3 are odd, all other terms are even.
%F a(0)=0, a(1)=1, a(n)=(a(n-1) XOR n) + a(n-2), where XOR is the bitwise exclusive-or operator.
%o (Python)
%o prpr = 0
%o prev = 1
%o for n in range(2,99):
%o current = (prev ^ n) + prpr
%o print prpr,
%o prpr = prev
%o prev = current
%K nonn,base,easy
%O 0,3
%A _Alex Ratushnyak_, May 03 2012