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A050415 Primes of the form 2^n - 3. 16
5, 13, 29, 61, 509, 1021, 4093, 16381, 1048573, 4194301, 16777213, 536870909, 19807040628566084398385987581, 83076749736557242056487941267521533, 5316911983139663491615228241121378301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

if p = 2^n - 3 is in this sequence, then p*2^(n-1) is abundant with abundance 2. - Claude Morin, Feb 01 2007

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..30

FORMULA

a(n) = 2^A050414(n) - 3.

MATHEMATICA

lst={}; Do[p=2^n-3; If[PrimeQ[p], AppendTo[lst, p]], {n, 0, 5*5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 27 2009 *)

Select[Table[2^n-3, {n, 1, 400}], PrimeQ] (* Vincenzo Librandi, Dec 08 2011 *)

PROG

(MAGMA) [a: n in [1..200] | IsPrime(a) where a is  2^n-3]; // Vincenzo Librandi, Dec 08 2011

(PARI) for(n=3, 999, if(ispseudoprime(t=2^n-3), print1(t", "))) \\ Charles R Greathouse IV, Jul 02 2013

CROSSREFS

Cf. A045768, A050414.

Sequence in context: A036982 A029580 A113914 * A099970 A073857 A295112

Adjacent sequences:  A050412 A050413 A050414 * A050416 A050417 A050418

KEYWORD

nonn

AUTHOR

Jud McCranie, Dec 22 1999

STATUS

approved

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Last modified July 22 09:46 EDT 2018. Contains 312891 sequences. (Running on oeis4.)