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A072125
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Concatenation of first n entries (digits) of A007376 is not divisible by 3.
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1
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1, 4, 7, 10, 11, 12, 14, 16, 17, 18, 20, 22, 23, 24, 26, 28, 29, 32, 34, 35, 38, 40, 41, 44, 46, 47, 53, 54, 59, 60, 65, 66, 70, 71, 72, 74, 76, 77, 78, 80, 82, 83, 84, 86, 88, 89, 92, 94, 95, 98, 100, 101, 104, 106, 107, 113, 114, 119, 120, 125, 126, 130, 131, 132, 134
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OFFSET
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1,2
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COMMENTS
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Concatenation of some permutations of the n digits of A007376 is likely to be prime.
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LINKS
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EXAMPLE
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16 is in the sequence because the 16-digit number 1234567891011121 = 1 (mod 3).
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MATHEMATICA
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f[0] = 0; f[n_Integer] := 10^(Floor[Log[10, n]] + 1)*f[n - 1] + n; Select[ Range[140], Mod[ FromDigits[ Take[ IntegerDigits[ f[n]], n]], 3] != 0 &]
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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