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