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A098556
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Least k such that k*Mersenne-prime(n)+1 is prime.
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2
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2, 4, 10, 4, 46, 12, 16, 46, 52, 136, 166, 114, 336, 154, 1474, 156, 1086, 1816, 2010, 9436, 1746, 3426, 6238, 40138, 858, 4018, 17262, 15418
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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MATHEMATICA
| mexp = {the list in A000043}; f[n_] := Block[{k = 2, mp = 2^mexp[[n]] - 1}, While[ !PrimeQ[mp*k + 1] && k < 10000, k += 2 ]; If[k == 10000, 0, k]]; Do[ Print[ f[n]], {n, 21}] (from Robert G. Wilson v Sep 17 2004)
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CROSSREFS
| Cf. A000043, A000668, A098555.
Sequence in context: A065299 A128942 A135445 * A159585 A130334 A200742
Adjacent sequences: A098553 A098554 A098555 * A098557 A098558 A098559
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KEYWORD
| hard,nonn
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AUTHOR
| Pierre CAMI (pierre-cami(AT)bbox.fr), Sep 14 2004
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EXTENSIONS
| a(21)=1746 corrected, other terms verified, a(23)-a(28) extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Apr 16 2009
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