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A065853
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Let u be any string of 4 digits from {0,...,n-1}; let f(u) = number of distinct primes, not beginning with 0, formed by permuting the digits of u to a base-n number; then a(n) = max_u f(u).
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11
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2, 4, 6, 7, 8, 15, 11, 11, 11, 15, 15, 19, 11, 14, 15, 14, 11, 16, 13, 18, 14, 14, 14, 16, 13, 16, 15, 17, 13, 16, 14, 15, 17, 16, 15, 16, 14, 17, 14, 17, 16, 17, 14, 16, 15, 15, 14, 17, 17, 16, 16, 16, 15, 18, 16, 17, 14, 15, 14, 16, 15, 15, 16, 16, 17, 17, 13, 17, 15, 17, 13
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OFFSET
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2,1
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LINKS
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EXAMPLE
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a(2)=2 because 1101 and 1011 are primes and there are no three 4-digit primes with the same number of ones in base 2.
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MATHEMATICA
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c[x_, n_] :=
Module[{},
Length[Select[Permutations[x],
First[#] != 0 && PrimeQ[FromDigits[#, n]] &]]];
Return[ Max[Map[c[#, n] &,
DeleteDuplicatesBy[Tuples[Range[0, n - 1], 4],
Table[Count[#, i], {i, 0, n - 1}] &]]]]];
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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