
Lite 
3, 5, 7, 9, ...
Category:  Series 
Submitted By:  snaps 
Fun:  (2.25) 
Difficulty:  (3.1) 
What three numbers come next in the following series?
1, 3, 5, 7, 9, 15, 17, 21, 27, __, __, __.
Answer:
31, 33, 45. Each number is the decimal value for the sequence of palindromic binary numbers, starting with (and finishing with) a 1. ie. 1=1, 3=11, 5=101, 7=111, 9=1001, 15=1111, 17=10001, 21=10101, 27=11011, 31=11111, 33=100001, 45=101101.
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