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A074755
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Number of n-digit non-leading-zero trimorphic numbers (m such that m^3 ends in m).
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1
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5, 7, 13, 11, 11, 13, 12, 13, 12, 13, 13, 11, 10, 12, 12, 13, 12, 12, 12, 11, 13, 12, 12, 10, 10, 13, 13, 13, 11, 13, 12, 10, 10, 11, 11, 13, 13, 10, 13, 11, 13, 12, 13, 12, 12, 13, 12, 12, 12, 12, 12, 11, 10, 10, 13, 13, 13, 13, 13, 13, 11, 13, 12, 10, 11, 11, 13
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OFFSET
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1,1
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COMMENTS
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For n >= 3, I can show 8 <= a(n) <= 13 and I highly suspect that 10 <= a(n) <= 13 from empirical evidence.
If n >= 3, there are 15 integers 0 <= x < 10^n with x == 0,1 or -1 mod 5^n and
x == 0, 1, -1, 2^(n-1)-1 or 2^(n-1)+1 mod 2^n, and a(n) is the number of these
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LINKS
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MAPLE
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f:= n ->
nops(select(`>=`, {seq(seq(chrem([a, b], [2^n, 5^n]), a={0, 1, 2^(n-1)-1, 2^(n-1)+1, -1}), b={0, 1, -1})}, 10^(n-1))):
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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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