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Search: id:A114756
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| A114756 |
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Smallest prime of the form: n successive positive integers in ascending order followed by a 7. |
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+0
8
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| 17, 127, 1237, 12347, 123457, 56789107, 456789107, 3456789107, 4567891011127, 616263646566676869707, 13141516171819202122237, 2021222324252627282930317, 151617181920212223242526277
(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) = 12347, four successive positive integers 1,2,3,4 in ascending order followed by a 7.
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MATHEMATICA
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a[n_]:=(For[m=1, (v={}; Do[v=Join[v, IntegerDigits[k]], {k, m, m+n-1}]); !PrimeQ[10FromDigits[v]+7], m++ ]; 10FromDigits[v]+7); Table[a[n], {n, 14}] - Farideh Firoozbakht
f[n_] := Block[{t = Range@n}, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {7}]; !PrimeQ@p, t++ ]; p]; Array[f, 14] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A114754, A114755, A114757, A114758, A114759, A112716, A108145.
Sequence in context: A036828 A142613 A066453 this_sequence A138640 A142676 A087191
Adjacent sequences: A114753 A114754 A114755 this_sequence A114757 A114758 A114759
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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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