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Search: id:A052080
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| A052080 |
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Concatenation of n consecutive descending numbers starting from a(n) produces the smallest possible prime of this form, O if no such prime exists. |
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+0
4
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| 2, 4, 0, 10, 7, 0, 73, 46, 0, 56, 219, 0, 25, 60, 0, 52, 117, 0, 535, 172
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Terms for n>6 calculated by Carlos Rivera (crivera(AT)primepuzzles.net) and Felice Russo (felice.russo(AT)katamail.com). First hard cases occur for n = 22, 88 and 110.
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LINKS
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C. Rivera, Prime Puzzle 78
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EXAMPLE
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For n = 8 we have a(8) = 46 so the eight consecutive descending numbers 46,45,44,43,42,41,40 and 39 concatenated together gives the smallest possible prime of this form, 4645444342414039.
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CROSSREFS
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Cf. A052077, A052078, A052079.
Sequence in context: A095059 A021419 A066529 this_sequence A073451 A078022 A106603
Adjacent sequences: A052077 A052078 A052079 this_sequence A052081 A052082 A052083
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KEYWORD
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nonn,base,hard
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AUTHOR
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Patrick De Geest (pdg(AT)worldofnumbers.com), Jan 15 2000.
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