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, 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

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