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A216099
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Period of powers of 3 mod 10^n.
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6
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4, 20, 100, 500, 5000, 50000, 500000, 5000000, 50000000, 500000000, 5000000000, 50000000000, 500000000000, 5000000000000, 50000000000000, 500000000000000, 5000000000000000, 50000000000000000, 500000000000000000
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OFFSET
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1,1
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LINKS
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FORMULA
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4*5^(n-1), n <= 4.
5*10^(n-2), n >= 5.
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MATHEMATICA
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Table[If[n<5, (4*5^n)/5, 10^n/20], {n, 20}] (* or *) Join[{4, 20, 100}, NestList[ 10#&, 500, 20]] (* Harvey P. Dale, May 31 2017 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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