

A281499


Write n in binary reflected Gray code, interchange the 1's and 0's, reverse the code and convert it back to decimal.


1



1, 0, 0, 2, 4, 0, 2, 6, 12, 4, 0, 8, 10, 2, 6, 14, 28, 12, 4, 20, 16, 0, 8, 24, 26, 10, 2, 18, 22, 6, 14, 30, 60, 28, 12, 44, 36, 4, 20, 52, 48, 16, 0, 32, 40, 8, 24, 56, 58, 26, 10, 42, 34, 2, 18, 50, 54, 22, 6, 38, 46, 14, 30, 62, 124, 60, 28, 92, 76, 12, 44, 108, 100, 36, 4, 68, 84, 20, 52, 116, 112, 48, 16, 80, 64, 0, 32, 96, 104, 40, 8, 72, 88, 24, 56, 120
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OFFSET

0,4


LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..10000


FORMULA

a(n) = A036044(A003188(n)).


EXAMPLE

For n = 11, the binary reflected Gray code for 11 is '1110' which after interchanging the 1's and 0's becomes '0001', which on reversing further gives '1000'. Now, 1000_2 = 8_10. So, a(11) = 8.


MATHEMATICA

Table[FromDigits[Reverse@ IntegerDigits[#, 2] &@ BitXor[n, Floor[n/2]] /. { 0 > 1, 1 > 0}, 2], {n, 0, 120}] (* Michael De Vlieger, Jan 23 2017 *)


PROG

(Python)
def G(n):
....return bin(n^(n/2))[2:]
def a(n):
....s=""
....x=G(n)
....for i in x:
........if i=="1":s+="0"
........else:s+="1"
....s=s[::1]
....return int(s, 2)


CROSSREFS

Cf. A003188, A014550, A036044.
Sequence in context: A279647 A028963 A004516 * A256014 A256280 A153182
Adjacent sequences: A281496 A281497 A281498 * A281500 A281501 A281502


KEYWORD

nonn,base


AUTHOR

Indranil Ghosh, Jan 23 2017


STATUS

approved



