|
|
A225584
|
|
Primes in the chain of repeated application of x->2*x+3, starting at x=23.
|
|
3
|
|
|
23, 101, 829, 6653, 13309, 6815741, 436207613, 13958643709, 27917287421, 468374361246531581, 3746994889972252669, 959230691832896684029, 16093220510709943573688614909
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[NestList[2 # + 3 &, 23, 30], PrimeQ] (* or *) Select[Table[13 2^(n+1) - 3, {n, 0, 150}], PrimeQ]
|
|
PROG
|
(Magma) x:=23; a:=[n eq 1 select x else 2*Self(n-1)+3: n in [1..200]]; [a[i]: i in [1..#a] | IsPrime(a[i])]; /* or */ [a: n in [0..150] | IsPrime(a) where a is 13*2^n-3]
|
|
CROSSREFS
|
Numbers of the form 13*2^m-3: A156202.
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|