|
|
A125871
|
|
Numbers n such that p=14n+1 is prime and cos(2pi/p) is an algebraic number of a 7-smooth degree, but not 5-smooth.
|
|
0
|
|
|
2, 3, 5, 8, 9, 14, 15, 20, 24, 27, 30, 32, 35, 45, 48, 50, 54, 63, 72, 75, 98, 105, 144, 162, 180, 189, 192, 200, 224, 240, 252, 300, 320, 420, 450, 500, 504, 525, 540, 560, 588, 630, 750, 768, 864, 875, 900, 960, 980, 1029, 1080, 1134, 1215, 1280, 1323
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Numbers n such that p=14n+1 is prime and the greatest prime divisor of p-1 is 7.
|
|
LINKS
|
|
|
MATHEMATICA
|
Do[If[Take[FactorInteger[EulerPhi[14n+1]][[ -1]], 1]=={7} && PrimeQ[14n+1], Print[n]], {n, 1, 10000}] (*Artur Jasinski*)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|