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A132171
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3^n repeated 3^n times.
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3
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1, 3, 3, 3, 9, 9, 9, 9, 9, 9, 9, 9, 9, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81, 81
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 3^floor(log_3(2n+1)).
a(3*n+1) = a(3*n+2) = a(3*n+3) = 3*a(n).
G.f.: (1-x)^(-1)*Sum_{m>=1} (3^m-3^(m-1))*x^((3^m-1)/2).
(End)
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MAPLE
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MATHEMATICA
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Table[ConstantArray[3^n, 3^n], {n, 0, 4}] // Flatten (* or *)
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PROG
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(Haskell)
import Data.List (transpose)
a132171 n = genericIndex a132171_list n
a132171_list = 1 : zs where
zs = 3 : 3 : 3 : (map (* 3) $ concat $ transpose [zs, zs, zs])
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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