A308269 Primes p such that 2*p^2 + 2*p - 9 is prime.
2, 7, 19, 37, 67, 109, 127, 157, 229, 349, 397, 457, 619, 727, 829, 877, 1117, 1129, 1237, 1249, 1279, 1327, 1447, 1459, 1489, 1699, 1777, 1789, 1867, 1879, 1987, 1999, 2179, 2269, 2377, 2389, 2467, 2539, 2647, 2659, 2767, 2857, 2917, 3019, 3109, 3169, 3187, 3217, 3229, 3307, 3319, 3457, 3637
Offset: 1
Keywords
Examples
a(3) = 19 is in the sequence because 19 and 2*19^2 + 2*19 - 9 = 751 are prime.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Crossrefs
Cf. A308268.
Programs
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Magma
[p:p in PrimesUpTo(5000)|IsPrime(2*p^2 + 2*p - 9)]; // Marius A. Burtea, May 17 2019
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Maple
select(p -> isprime(p) and isprime(2*p^2 + 2*p - 9), [2,seq(i,i=7..1000,6)]);
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Mathematica
Select[Prime[Range[600]],PrimeQ[2#^2+2#-9]&] (* Harvey P. Dale, Jun 14 2021 *)
Comments