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A110430
Arithmetic mean of all n-digit positive even numbers.
2
5, 54, 549, 5499, 54999, 549999, 5499999, 54999999, 549999999, 5499999999, 54999999999, 549999999999, 5499999999999, 54999999999999, 549999999999999, 5499999999999999, 54999999999999999, 549999999999999999, 5499999999999999999
OFFSET
0,1
FORMULA
a(n) =1/2{10^(n-1) + 10^n -2}
EXAMPLE
a(2) = Arithmetic mean of 10,12,14,...96,98 =(10 + 98)/2 =54.
MATHEMATICA
Table[FromDigits[PadRight[{5, 4}, n, 9]], {n, 20}] (* Harvey P. Dale, Apr 24 2020 *)
CROSSREFS
Sequence in context: A268882 A229298 A087125 * A110432 A215542 A304322
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Aug 02 2005
EXTENSIONS
Corrected and extended by Joshua Zucker, May 10 2006
STATUS
approved