# An omalonumerophobic's number sequence

Find all seven terms of the number sequence,

a1, a2, a3, a4, a5, a6, a7

given that

• each successive term is exactly twice the value of the previous term
• no even digits are used in writing the terms

The ai are integers written in decimal notation.

Thanks to @GOTO 0 for the inspiration.

• Yes - thanks boboquack - your words are good (and help to rule out more lateral thinking). – Tom Sep 21 '17 at 4:13
• @Tom they're your words :P – boboquack Sep 21 '17 at 4:19
• Decimal notation definitely means base 10, correct? – Hugh Meyers Sep 22 '17 at 12:30
• Yes, base ten decimal representation. – Tom Sep 22 '17 at 12:44

$5, 9.\bar{9},19.\bar{9},39.\bar{9},79.\bar{9},159.\bar{9},319.\bar{9}$.