OFFSET
1,12
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..10000
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
KEYWORD
nonn,base
AUTHOR
Indranil Ghosh, Jan 23 2017
STATUS
approved