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A004167
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Powers of 3 written backwards.
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18
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1, 3, 9, 72, 18, 342, 927, 7812, 1656, 38691, 94095, 741771, 144135, 3234951, 9692874, 70984341, 12764034, 361041921, 984024783, 7641622611, 1044876843, 30235306401, 90695018313, 72887134149, 184635924282, 344906882748, 9238285681452, 7894847955267
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listen;
history;
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OFFSET
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0,2
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COMMENTS
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From a(2) onwards, all terms are divisible by 9. - Alonso del Arte, Apr 04 2014
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LINKS
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FORMULA
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EXAMPLE
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a(5) = 342 since 3^5 = 243.
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MAPLE
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a:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||(3^n)):
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MATHEMATICA
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Table[FromDigits[Reverse[IntegerDigits[3^n]]], {n, 0, 26}] (* Alonso del Arte, Apr 04 2014 *)
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PROG
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(Python)
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CROSSREFS
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The following are parallel families: A000079 (2^n), A004094 (2^n reversed), A028909 (2^n sorted up), A028910 (2^n sorted down), A036447 (double and reverse), A057615 (double and sort up), A263451 (double and sort down); A000244 (3^n), A004167 (3^n reversed), A321540 (3^n sorted up), A321539 (3^n sorted down), A163632 (triple and reverse), A321542 (triple and sort up), A321541 (triple and sort down).
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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