A204771 - OEIS

%I #30 May 21 2021 08:08:50

%S 0,1,1,2,1,7,4,17,29,46,121,243,408,833,1929,3658,6353,12815,30844,

%T 61009,100133,216534,514233,930107,1686288,3352737,8264081,15163506,

%U 27077825,53153175,133991380,243114769,428343405,854649182,2120804377,3870970883,6937439304

%N a(n) = a(n-1) XOR (a(n-2)*3).

%H Ivan Panchenko, <a href="/A204771/b204771.txt">Table of n, a(n) for n = 0..200</a>

%F a(0)=0, a(1)=1, a(n) = a(n-1) XOR (a(n-2)*3), where XOR is the bitwise exclusive-OR operator.

%o (Python)

%o prpr = 0

%o prev = 1

%o for i in range(99):

%o     current = (prev)^(prpr*3)

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

%o     prpr = prev

%o     prev = current

%Y Cf. A101624: a(n) = a(n-1) XOR (a(n-2)*2).

%Y Cf. A101625: a(n) = a(n-1) XOR (a(n-2)*4).

%K nonn,base,easy

%O 0,4

%A _Alex Ratushnyak_, May 07 2012