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 A281388 Write n in binary reflected Gray code and sum the positions where there is a '1' followed immediately to the right by a '0', counting the leftmost digit as position 1. 3
 0, 0, 1, 2, 0, 1, 1, 2, 2, 0, 3, 4, 1, 1, 1, 2, 2, 2, 6, 4, 0, 3, 3, 4, 4, 1, 5, 5, 1, 1, 1, 2, 2, 2, 7, 7, 2, 6, 6, 4, 4, 0, 5, 8, 3, 3, 3, 4, 4, 4, 9, 6, 1, 5, 5, 5, 5, 1, 6, 6, 1, 1, 1, 2, 2, 2, 8, 8, 2, 7, 7, 7, 7, 2, 8, 12, 6, 6, 6, 4, 4, 4, 10, 6, 0, 5, 5, 8, 8, 3, 9, 9, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Indranil Ghosh, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A049501(A003188(n)). EXAMPLE For n = 11, the binary reflected Gray code for 11 is '1110'. In '1110', the position of '1' followed immediately to the right by '0' counting from left is 3. So, a(11) = 3. For n = 12, the binary reflected Gray code for 12 is '1010'. In '1010', the positions of '1' followed immediately to the right by '0' counting from left are 1 and 3. So, a(12) = 1 + 3 = 4. PROG (Python) def g(n): ....return bin(n^(n/2))[2:] def a(n): ....x=g(n) ....s=0 ....for i in range(1, len(x)): ........if x[i-1]=="1" and x[i]=="0": ............s+=i ....return s CROSSREFS Cf. A003188, A014550, A049501. Sequence in context: A236532 A077763 A030218 * A127440 A118198 A290885 Adjacent sequences:  A281385 A281386 A281387 * A281389 A281390 A281391 KEYWORD nonn,base AUTHOR Indranil Ghosh, Jan 21 2017 STATUS approved

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Last modified May 12 12:47 EDT 2021. Contains 343823 sequences. (Running on oeis4.)