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A281553
Write n in binary reflected Gray code, rotate one binary place to the right and convert the code back to decimal.
1
0, 1, 3, 1, 3, 7, 6, 2, 6, 14, 15, 7, 5, 13, 12, 4, 12, 28, 29, 13, 15, 31, 30, 14, 10, 26, 27, 11, 9, 25, 24, 8, 24, 56, 57, 25, 27, 59, 58, 26, 30, 62, 63, 31, 29, 61, 60, 28, 20, 52, 53, 21, 23, 55, 54, 22, 18, 50, 51, 19, 17, 49, 48, 16, 48, 112, 113, 49, 51, 115, 114, 50, 54, 118
OFFSET
0,3
COMMENTS
a(n) = A003188(n), iff the Elias delta code for n contains all 1's without any zeros (see the example section).
LINKS
EXAMPLE
For n = 5, the binary reflected Gray code for n is '111'. Rotating one binary place to the right , '111' gives back '111' again. 111_2 = 7_10. So, a(5) = 7. (For n = 5, A003188(n) = 7).
For n = 15, the binary reflected Gray code for n is '1000'. Rotating one binary place to the right, '1000' gives '0100'. 100_2 = 4_10. So, a(15) = 4.
PROG
(Python)
def rotation(n):
....x=bin(n^(n/2))[2:]
....return int(x[-1]+x[:-1], 2)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Indranil Ghosh, Jan 24 2017
STATUS
approved