A144620 Numbers k such that k and 19*k + 8 are both prime.
5, 17, 41, 59, 89, 167, 191, 239, 269, 281, 359, 449, 479, 491, 509, 521, 587, 617, 647, 701, 719, 821, 881, 911, 929, 971, 1031, 1181, 1217, 1259, 1289, 1307, 1361, 1367, 1559, 1601, 1697, 1709, 1721, 1787, 1877, 1889, 1907, 1931, 1949, 1997, 2039, 2129
Offset: 1
Examples
For n=5, 19*5 + 8 = 103; for n=269, 19*269 + 8 = 5119.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Programs
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Magma
[p: p in PrimesUpTo(2500)|IsPrime(19*p+8)] // Vincenzo Librandi, Aug 30 2012
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Maple
a := proc (n) if isprime(n) = true and isprime(19*n+8) = true then n else end if end proc: seq(a(n), n = 1 .. 2300); # Emeric Deutsch, Jan 27 2009
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Mathematica
Select[Prime[Range[400]], PrimeQ[#] &&PrimeQ[19#+8] &] (* Vincenzo Librandi, Aug 30 2012 *)
Extensions
Extended by Emeric Deutsch, Jan 27 2009