|
|
A124492
|
|
a(n) = least k such that 2*i*k - 1 is prime for 1 <= i <= n.
|
|
7
|
|
|
2, 2, 2, 3, 3, 77385, 1447110, 1447110, 203937090, 107290072890, 4724240531010, 123618251967210, 1272603355923900, 9089306184994125090
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
MATHEMATICA
|
a[n_] := Block[{k = If[n < 6, 1, 5], s}, s = k; While[! AllTrue[k 2 Range[n] - 1, PrimeQ], k += s]; k]; Array[a, 8] (* Giovanni Resta, Apr 01 2017 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
EXTENSIONS
|
Corrected and extended by Don Reble, Nov 05 2006
|
|
STATUS
|
approved
|
|
|
|