|
|
A098471
|
|
Least k such that Mersenne-prime(n)*2^k+1 is prime (A000668(n)*2^k+1).
|
|
1
|
|
|
1, 2, 8, 2, 12, 864, 4, 10, 8, 72, 18, 38, 2144, 178, 472, 974, 2200, 8128, 4580, 822, 3600, 4100
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
MATHEMATICA
|
mexp = {the list in A000043}; f[n_] := Block[{k = 1, mp = 2^mexp[[n]] - 1}, While[ !PrimeQ[mp*2^k + 1] && k < 10000, k++ ]; If[k == 10000, 0, k]]; Do[ Print[ f[n]], {n, 22}] (* Robert G. Wilson v, Sep 13 2004 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|