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 A281497 Write n in binary reflected Gray code and sum the positions where there is a '1' followed immediately to the left by a '0', counting the rightmost digit as position 1. 2
 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 2, 2, 1, 0, 0, 1, 2, 2, 0, 0, 1, 0, 3, 4, 3, 3, 2, 2, 1, 0, 0, 1, 2, 2, 3, 3, 4, 3, 0, 1, 0, 0, 2, 2, 1, 0, 4, 5, 6, 6, 4, 4, 5, 4, 3, 4, 3, 3, 2, 2, 1, 0, 0, 1, 2, 2, 3, 3, 4, 3, 4, 5, 4, 4, 6, 6, 5, 4, 0, 1, 2, 2, 0, 0, 1, 0, 3, 4, 3, 3, 2, 2, 1, 0, 5, 6, 7, 7, 8, 8, 9, 8, 5, 6, 5, 5, 7, 7, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,12 LINKS Indranil Ghosh, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A049502(A003188(n)). EXAMPLE For n = 12, the binary reflected Gray code for 12 is '1010'. In '1010', the position of '1' followed immediately to the left by a '0' counting from right is 2. So, a(12) = 2. MATHEMATICA Table[If[Length@ # == 0, 0, Total[#[[All, 1]]]] &@ SequencePosition[ Reverse@ IntegerDigits[#, 2] &@ BitXor[n, Floor[n/2]], {1, 0}], {n, 120}] (* Michael De Vlieger, Jan 23 2017, Version 10.1, after Robert G. Wilson v at A003188 *) PROG (Python) def G(n): ....return bin(n^(n/2))[2:] def a(n): ....x=G(n)[::-1] ....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, A049502, A281388. Sequence in context: A276204 A347883 A024712 * A198243 A164965 A021823 Adjacent sequences:  A281494 A281495 A281496 * A281498 A281499 A281500 KEYWORD nonn,base AUTHOR Indranil Ghosh, Jan 23 2017 STATUS approved

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Last modified December 7 05:22 EST 2021. Contains 349567 sequences. (Running on oeis4.)