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Search: id:A086884
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| A086884 |
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Smallest string of 1's and 0's which is prime in every base from 2 to n. |
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+0
2
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| 10, 10, 101111, 10010111, 111110100001, 111110100001, 11000011101101111, 10011110011011110110110011, 110100000010101111110001010011001110001
(list; graph; listen)
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OFFSET
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2,1
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LINKS
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Phil Carmody, Bitstrings representing primes in many bases.
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EXAMPLE
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a(5) = 10010111 because 10010111 (base 2) = 151, 10010111 (base 3) = 2281, 10010111 (base 4) = 16661 and 10010111 (base 5) = 78781 are all prime and 10010111 is smallest such string.
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MATHEMATICA
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a[n_] := (While[b = FromDigits[ IntegerDigits[k, 2]]; Union[ PrimeQ[ Table[ FromDigits[ IntegerDigits[b], i], {i, 2, n}]]] != {True}, k++ ]; b); k = 1; Do[ Print[ a[n]], {n, 2, 10}]
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CROSSREFS
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See A086204 for decimal equivalents.
Adjacent sequences: A086881 A086882 A086883 this_sequence A086885 A086886 A086887
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KEYWORD
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nonn,new
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AUTHOR
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Richard FitzHugh (fitzhughrichard(AT)hotmail.com), Aug 22 2003
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EXTENSIONS
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Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 24 2003
a(10) from Phil Carmody's Web site added by Dario A. Alpern (alpertron(AT)hotmail.com), May 14 2006
Cross-reference changed from A096204 to A086204 James G. Merickel (merk7(AT)verizon.net), Nov 18 2009
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