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A176011
Primes in the chain of repeated application of x->2*x+3, starting at x=97.
1
97, 197, 397, 797, 1597, 6397, 51197, 102397, 204797, 409597, 13107197, 209715197, 1677721597, 107374182397, 1717986918397, 54975581388797, 14073748835532797, 3602879701896396797, 461168601842738790397, 1888946593147858085478397, 3868562622766813359059763197
OFFSET
1,1
COMMENTS
All terms are of the form 100*2^k-3. [Bruno Berselli, May 14 2013]
LINKS
EXAMPLE
97*2+3=197 is prime, therefore it is in the sequence; 1597*2+3=3197 is not prime, therefore it is not in the sequence.
MATHEMATICA
Select[NestList[2 # + 3 &, 97, 30], PrimeQ] (* Vincenzo Librandi, May 14 2013 *)
PROG
(Magma) x:=97; a:=[n eq 1 select x else 2*Self(n-1)+3: n in [1..100]]; [a[i]: i in [1..#a] | IsPrime(a[i])]; // Bruno Berselli, May 14 2013
CROSSREFS
Sequence in context: A044429 A044810 A244778 * A157410 A142504 A261109
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 06 2010
EXTENSIONS
51197 added by Bruno Berselli, May 14 2013
STATUS
approved