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A098556
Least k such that k*Mersenne - prime(n) + 1 is prime.
2
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
OFFSET
1,1
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}] (* Robert G. Wilson v, Sep 17 2004 *)
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Pierre CAMI, Sep 14 2004
EXTENSIONS
a(21)=1746 corrected, other terms verified, a(23)-a(28) extended by Ray Chandler, Apr 16 2009
STATUS
approved