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Search: id:A114759
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| A114759 |
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Smallest prime of the form: n successive positive integers in descending order followed by a 3. a(3k) = 0 as no such prime exists. |
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+0
8
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| 13, 433, 0, 54323, 654323, 0, 292827262524233, 987654323, 0, 1716151413121110983, 181716151413121110983, 0, 1413121110987654323, 27262524232221201918171615143, 0, 1716151413121110987654323
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(4) = 54323, four successive positive integers 5,4,3,2 in descending order followed by a 3.
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MATHEMATICA
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a[n_]:=If[Mod[n, 3]==0, 0, (For[m=1, (v={}; Do[v=Join[v, IntegerDigits[k]], {k, m+n-1, m, -1}]); !PrimeQ[10FromDigits[v]+3], m++ ]; 10FromDigits[v] +3)]; Table[a[n], {n, 17}] - Farideh Firoozbakht
f[n_] := Block[{t = Reverse@Range@n}, If[Mod[n, 3] == 0, 0, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {3}]; ! PrimeQ@p, t++ ]; p]]; Array[f, 18] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A114754, A114755, A114756, A114757, A114758, A112716, A108145.
Sequence in context: A012045 A012109 A012084 this_sequence A012832 A102075 A081862
Adjacent sequences: A114756 A114757 A114758 this_sequence A114760 A114761 A114762
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jan 01 2006
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EXTENSIONS
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Extended by Robert G. Wilson v (rgwv(at)rgwv.com), Ray Chandler (rayjchandler(AT)sbcglobal.net) and Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Jan 02 2006
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