A068712 Primes of the form 5*2^k + 3.
13, 23, 43, 83, 163, 643, 1283, 10243, 20483, 1310723, 5242883, 335544323, 1342177283, 21474836483, 85899345923, 43980465111043, 87960930222083, 5629499534213123, 22517998136852483, 1441151880758558723
Offset: 1
Keywords
Examples
1283 is a term as a concatenation of 2^7 and 3.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..38
Programs
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Magma
[a: n in [1..100] | IsPrime(a) where a is 5*2^n + 3]; // Vincenzo Librandi, Dec 08 2011
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Mathematica
Select[5*2^Range[60]+3, PrimeQ] (* Harvey P. Dale, Feb 04 2011 *)
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PARI
for(n=1,150, if(isprime(2^n*5+3)==1,print1(2^n*5+3,",")))
Extensions
More terms from Benoit Cloitre, Mar 09 2002