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A076449
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Least number which has n embedded primes.
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4
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1, 2, 25, 13, 37, 107, 127, 113, 167, 1027, 179, 137, 1036, 1127, 1013, 1137, 1235, 1136, 1123, 1037, 1139, 1079, 10124, 10126, 1349, 1279, 11237, 3479, 10699, 1367, 10179, 1379, 10127, 10079, 10138, 10123, 10234, 10235, 10247, 10339, 10267
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OFFSET
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0,2
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COMMENTS
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Smallest m such that A075053(m) = n.
Keith conjectures that a(n) always exists and reports that he has checked this for n <= 66. - N. J. A. Sloane, Jan 25 2008
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LINKS
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Table of n, a(n) for n=0..40.
C. K. Caldwell, The Prime Glossary, Primeval Number
J. P. Delahaye, Primes Hunters, 1379 is very primeval (in French)
M. Keith, Integers containing many embedded primes
W. Schneider, PrimevalNumbers
G. Villemin's Almanach of Numbers, Nombre Primeval de Mike Keith
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EXAMPLE
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a(10)=179 because 179 is the least number harbouring ten primes (namely 7, 17, 19, 71, 79, 97, 179, 197, 719, 971).
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MATHEMATICA
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(* first do *) Needs["DiscreteMath`Combinatorica`"] (* then *) f[n_] := Length[ Select[ FromDigits /@ Flatten[ Permutations /@ Subsets[ IntegerDigits[ n]], 1], PrimeQ[ # ] &]]; t = Table[0, {50}]; Do[ a = f[n]; If[a < 50 && t[[a + 1]] == 0, t[[a + 1]] = n], {n, 12500}]; t (from Robert G. Wilson v Feb 12 2005)
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CROSSREFS
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Cf. A075053. A072857 gives a similar sequence.
Sequence in context: A065665 A161575 A036502 * A153811 A101962 A092045
Adjacent sequences: A076446 A076447 A076448 * A076450 A076451 A076452
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KEYWORD
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base,nonn,changed
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AUTHOR
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Lekraj Beedassy, Nov 07 2002
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EXTENSIONS
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Edited by Robert G. Wilson v, Nov 24 2002
Keith link repaired by Charles R Greathouse IV, Aug 13 2009
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STATUS
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approved
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