A153590 Primes p such that p^2 + 3p + 1 is also prime.
2, 3, 5, 7, 19, 23, 29, 37, 43, 47, 53, 59, 67, 113, 137, 139, 157, 163, 173, 179, 229, 239, 257, 263, 293, 313, 349, 353, 359, 373, 379, 419, 449, 467, 499, 503, 509, 547, 577, 587, 593, 617, 643, 647, 653, 719, 727, 797, 883, 929, 967, 983, 997, 1013, 1033, 1049
Offset: 1
Examples
For p = 2, p^2 + 3p + 1 = 11; p = 67, p^2 + 3p + 1 = 4691; for p = 419, p^2 + 3p + 1 = 176819.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Crossrefs
Programs
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Magma
[ p: p in PrimesUpTo(1050) | IsPrime(p^2+3*p+1) ];
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Mathematica
Select[Table[Prime[n],{n,6!}], PrimeQ[#^2+3*#+1]&] (* Vladimir Joseph Stephan Orlovsky, Mar 13 2010 *)
Extensions
Edited and extended by Klaus Brockhaus, Jan 01 2009
Comments