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A110431
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Average of positive multiples of 3 with n decimal digits, rounded down.
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1
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6, 55, 550, 5500, 55000, 550000, 5500000, 55000000, 550000000, 5500000000, 55000000000, 550000000000, 5500000000000, 55000000000000, 550000000000000, 5500000000000000, 55000000000000000, 550000000000000000, 5500000000000000000
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OFFSET
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1,1
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COMMENTS
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Subsidiary sequence: Average of positive multiples of k with n decimal digits, rounded down.
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LINKS
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Table of n, a(n) for n=1..19.
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FORMULA
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For n > 1, a(n+1) = 10 * a(n).
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EXAMPLE
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a(2) = average {12,15,...96,99} = floor((12+99)/2) = 55.
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PROG
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(PARI) a(n)=(11*10^(n-1)+1)\2
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CROSSREFS
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Cf. A110430.
Sequence in context: A342388 A253475 A215853 * A121661 A118836 A079589
Adjacent sequences: A110428 A110429 A110430 * A110432 A110433 A110434
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KEYWORD
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nonn,base
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AUTHOR
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Amarnath Murthy, Aug 02 2005
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EXTENSIONS
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Corrected and extended by Joshua Zucker, May 10 2006
Formula and program from Charles R Greathouse IV, Aug 03 2010
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STATUS
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approved
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