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A125725
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Numbers whose base 7 representation is 222....2.
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0
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0, 2, 16, 114, 800, 5602, 39216, 274514, 1921600, 13451202, 94158416, 659108914, 4613762400, 32296336802, 226074357616, 1582520503314, 11077643523200, 77543504662402, 542804532636816, 3799631728457714, 26597422099204000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| a(n)=2*(7^(n-1)-1)/6.
a(n)=7*a(n-1)+2 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Sep 30 2010]
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EXAMPLE
| base 7.......decimal
0..................0
2..................2
22................16
222..............114
2222.............800
22222...........5602
222222.........39216
2222222.......274514
22222222.....1921600
222222222...13451202
etc...........etc.
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MAPLE
| seq(2*(7^n-1)/6, n=0..20);
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MATHEMATICA
| FromDigits[#, 7]&/@Table[PadLeft[{2}, n, 2], {n, 0, 25}] (* From Harvey P. Dale, Apr 13 2011 *)
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CROSSREFS
| Sequence in context: A117627 A117628 A037564 * A162723 A193289 A159324
Adjacent sequences: A125722 A125723 A125724 * A125726 A125727 A125728
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KEYWORD
| easy,nonn
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AUTHOR
| Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 02 2007
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EXTENSIONS
| Offset corrected by N. J. A. Sloane, Oct 02 2010
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