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Search: id:A073928
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| A073928 |
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Smallest prime q of form q=-1+(c+1)*10^w, where c runs through composites not divisible by 3. |
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+0
1
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| 499, 89, 109, 149, 1699, 2099, 229, 25999, 269, 289999, 3299, 349, 359, 389, 409, 449, 469999999999999999, 499, 509, 52999, 5599999, 569, 58999999999999999, 6299, 64999999999999, 659, 6899, 709, 7499, 769, 77999, 809, 829, 859, 8699
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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88 is the 36th composite which is not divisible by 3; a(36)=-1+(88+1)*10^33=88999999999999999999999999999999999, i.e. 88 followed by 33 copies of digit 9.
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MATHEMATICA
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c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] Table[fl=1; k=0; Do[s=(c[m]+1)*10^n-1; If[PrimeQ[s]&&(fl==1)&&!Equal[Mod[c[m], 3], 0], Print[s]; fl=0], {n, 1, 100}], {m, 1, 256}]
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CROSSREFS
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Cf. A055785, A002808.
Sequence in context: A064255 A067917 A093249 this_sequence A045299 A106761 A093945
Adjacent sequences: A073925 A073926 A073927 this_sequence A073929 A073930 A073931
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KEYWORD
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base,nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Sep 03 2002
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