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A172156 Primes in the chain of repeated application of x->2*x+3, starting at x=2. 5
7, 17, 37, 157, 317, 1277, 2557, 20477, 655357, 5242877, 671088637, 2684354557, 5368709117, 343597383677, 23058430092136939517, 23611832414348226068477, 48357032784585166988247037, 830767497365572420564879412675215357 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..37

MATHEMATICA

Rest[Select[NestList[2#+3&, 2, 500], PrimeQ]] (* Harvey P. Dale, Nov 17 2012 *)

PROG

(MAGMA) x:=2; a:=[n eq 1 select 2*x+3 else 2*Self(n-1)+3: n in [1..120]]; [a[i]: i in [1..#a] | IsPrime(a[i])]; // Bruno Berselli, May 14 2013

CROSSREFS

Cf. A154117. [Klaus Brockhaus, Feb 28 2010]

Sequence in context: A211476 A155007 A214634 * A273947 A140121 A102770

Adjacent sequences:  A172153 A172154 A172155 * A172157 A172158 A172159

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Jan 27 2010

STATUS

approved

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Last modified November 14 10:04 EST 2019. Contains 329111 sequences. (Running on oeis4.)