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Search: id:A052079
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| A052079 |
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Concatenation of n consecutive ascending 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, 2, 0, 4, 15, 0, 7, 2, 0, 4, 129, 0, 5, 50, 0, 128, 3, 0, 23, 38, 0, 9998, 17, 0, 25, 2, 0, 16, 341, 0, 569, 42, 0, 14, 1203, 0, 2465, 102, 0, 212, 1161, 0, 197
(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 with n = 44 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 = 7 we have a(7) = 7 so the seven consecutive ascending numbers 7,8,9,10,11,12 and 13 concatenated together gives the smallest possible prime of this form, 78910111213.
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CROSSREFS
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Cf. A052077, A052078, A052080.
Sequence in context: A084102 A160125 A151868 this_sequence A166299 A088972 A100334
Adjacent sequences: A052076 A052077 A052078 this_sequence A052080 A052081 A052082
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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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EXTENSIONS
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Next term a(44)=10^348-32 (only probable prime with 15324 digits). a(110)=9999968. If n is divisible by 22 then either a(n)=0 or a(n)=10^x-b for some b<n. - Jens Kruse Andersen (jens.k.a(AT)get2net.dk), Feb 03 2003
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