A072998 To get a(n), write n in balanced ternary notation (using only digits -1, 0, 1, -1), then change -1's to 0's, 0's to 1's, and 1's to 2's.

1, 2, 20, 21, 22, 200, 201, 202, 210, 211, 212, 220, 221, 222, 2000, 2001, 2002, 2010, 2011, 2012, 2020, 2021, 2022, 2100, 2101, 2102, 2110, 2111, 2112, 2120, 2121, 2122, 2200, 2201, 2202, 2210, 2211, 2212, 2220, 2221, 2222, 20000, 20001, 20002, 20010

Offset: 0

Author

Robert G. Wilson v, Aug 15 2002

Keywords

• base
• nonn

Examples

			n balanced ternary a(n)
-----------------------
0........0...........1
1........1...........2
2......1,-1..........2,0
3.......1,0..........2,1
...
11 in base 10 = 11_10 = {1,1,-1} in balanced ternary = 1*3^2 + 1*3^1 - 1*3^0. Add 111 to {1,1,-1} to get a(11) = 220.
		

Extensions

Corrected by Reinhard Zumkeller, Aug 18 2008

Edited by N. J. A. Sloane, Mar 31 2021