A283979 - OEIS

%I #11 Mar 29 2017 20:25:56

%S 0,0,0,0,0,1,0,0,0,3,2,3,0,3,0,0,0,7,6,5,4,4,6,7,0,5,6,5,0,7,0,0,0,15,

%T 14,9,12,10,10,9,8,10,8,8,12,10,14,15,0,9,10,15,12,14,10,9,0,9,14,9,0,

%U 15,0,0,0,31,30,17,28,22,18,21,24,20,20,18,20,16,18,17,16,22,20,22,16,21,16,16,24,16,20,18,28,22,30,31,0,17,18,27,20,28,30

%N a(n) = (n XOR A264977(n))/4, where XOR is bitwise-xor (A003987).

%H Antti Karttunen, <a href="/A283979/b283979.txt">Table of n, a(n) for n = 0..8191</a>

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

%F a(n) = (n XOR A264977(n))/4, where XOR is bitwise-xor (A003987).

%t A264977[n_]:= If[n<2, n, If[EvenQ[n], 2 A264977[n/2], BitXor[A264977[(n - 1)/2], A264977[(n + 1)/2]]]]; Table[BitXor[n, A264977[n]]/4, {n, 0, 100}] (* _Indranil Ghosh_, Mar 28 2017 *)

%o (Scheme) (define (A283979 n) (/ (A003987bi n (A264977 n)) 4)) ;; Where A003987bi implements bitwise-xor (A003987).

%o (PARI) a(n) = if(n<2, n, if(n%2, bitxor(a((n - 1)/2), a((n + 1)/2)), 2*a(n/2)));

%o for(n=0, 150, print1(bitxor(n, a(n))/4,", ")) \\ _Indranil Ghosh_, Mar 28 2017

%Y Cf. A003987, A264977, A265397, A284013.

%K nonn,base,look

%O 0,10

%A _Antti Karttunen_, Mar 25 2017