A176011 Primes in the chain of repeated application of x->2*x+3, starting at x=97.

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

Vincenzo Librandi, Table of n, a(n) for n = 1..49

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

Adjacent sequences: A176008 A176009 A176010 * A176012 A176013 A176014

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 06 2010

Extensions

51197 added by Bruno Berselli, May 14 2013

Status

approved