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Search: id:A086122
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| A086122 |
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Primes generated by the linear recursion a[n]=5a[n-1]+1, a[0]=1. |
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4
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| 31, 19531, 12207031, 305175781, 177635683940025046467781066894531, 14693679385278593849609206715278070972733319459651094018859396328480215743184089660644531, 35032461608120426773093239582247903282006548546912894293926707097244777067146515037165954709053039550781
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Also a(n) are the primes in A003463(n), or primes of the form (5^n - 1)/4. Corresponding numbers n such that (5^n - 1)/4 is prime are listed in A004061(n) = {3,7,11,13,47,127,149,181,619,929,...}. - Alexander Adamchuk (alex(AT)kolmogorov.com), Jan 23 2007
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FORMULA
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a(n) = (5^A004061(n) - 1)/4 = A003463[ A004061(n) ]. - Alexander Adamchuk (alex(AT)kolmogorov.com), Jan 23 2007
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MATHEMATICA
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Do[f=(5^n-1)/4; If[PrimeQ[f], Print[{n, f}]], {n, 1, 1000}] - Alexander Adamchuk (alex(AT)kolmogorov.com), Jan 23 2007
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CROSSREFS
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Cf. A000668, A076481.
Cf. A003463, A004061, A074479.
Sequence in context: A069451 A073099 A074218 this_sequence A033176 A117579 A107122
Adjacent sequences: A086119 A086120 A086121 this_sequence A086123 A086124 A086125
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jul 23 2003
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EXTENSIONS
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More terms from Alexander Adamchuk (alex(AT)kolmogorov.com), Jan 23 2007
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