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A224475
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(2*5^(2^n) + (10^n)/2 - 1) mod 10^n: a sequence of trimorphic numbers ending (for n > 1) in 9.
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4
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4, 99, 749, 6249, 31249, 281249, 781249, 75781249, 925781249, 1425781249, 86425781249, 336425781249, 4836425781249, 69836425781249, 19836425781249, 7519836425781249, 62519836425781249, 12519836425781249, 9512519836425781249, 34512519836425781249
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OFFSET
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1,1
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COMMENTS
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a(n) is the unique positive integer less than 10^n such that a(n) + 2^(n-1) - 1 is divisible by 2^n and a(n) + 1 is divisible by 5^n.
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LINKS
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FORMULA
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a(n) = (A224473(n) + 10^n / 2) mod 10^n.
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PROG
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(Sage) def A224475(n) : return crt(2^(n-1)+1, -1, 2^n, 5^n)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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