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%I #2 May 01 2014 02:43:29
%S 0,1,2,1,4,3,2,3,8,5,6,5,4,3,6,3,16,9,10,9,12,7,10,7,8,5,6,5,12,7,6,7,
%T 32,17,18,17,20,11,18,11,24,13,14,13,20,11,14,11,16,9,10,9,12,7,10,7,
%U 24,13,14,13,12,7,14,7,64,33,34,33,36,19,34,19,40,21,22,21,36,19,22,19
%N Starting from the right (the least significant end) rewrite 0 to 0 and x1 to 1 in the binary expansion of n.
%e I.e. 23 is 10111 in binary, which after rewriting is 111, thus a(23) = 7, while 38 is 100110 in binary, which after the rewriting is 10010, i.e. a(38) = 18.
%o (MIT Scheme) (define (A072650 n) (let loop ((n n) (s 0) (i 0)) (cond ((zero? n) s) ((even? n) (loop (floor->exact (/ n 2)) s (1+ i))) (else (loop (floor->exact (/ n 4)) (+ s (expt 2 i)) (1+ i))))))
%Y Cf. A048679(n) = A072650(A003714(n)).
%K nonn
%O 0,3
%A _Antti Karttunen_, Jun 02 2002
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