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Search: id:A140959
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| A140959 |
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Number of distinct-digit primes in base n. |
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+0
1
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OFFSET
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1,3
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EXAMPLE
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a(1) = 0; a(2) = 1 since only the prime 2 in base 2 has distinct integers, 10_2;
a(3) = 6 since the primes {2, 3, 5, 7, 11 & 19} in base 3 have distinct integers, {2_3, 10_3, 12_3, 21_3, 102_3, 201_3}; etc.
a(10) = 283086 because it is the partial sum of A073532.
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MATHEMATICA
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f[b_] := Block[{c = 0, k = 1, lmt = b^b}, While[p = Prime@ k; p < lmt, k++; If[ Union[ Length /@ Split@ Sort@ IntegerDigits[p, b]] == {1}, c++ ]]; c]; Array[f, 6]
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CROSSREFS
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Cf. A073532.
Adjacent sequences: A140956 A140957 A140958 this_sequence A140960 A140961 A140962
Sequence in context: A147799 A071021 A074002 this_sequence A015699 A111437 A056464
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KEYWORD
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base,hard,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 25 2008
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