A193266 Numbers n such that n + 3 and n^2 + 9 are primes.

2, 8, 10, 20, 38, 40, 58, 70, 98, 100, 110, 160, 170, 188, 190, 220, 308, 350, 380, 538, 568, 598, 628, 640, 680, 688, 698, 740, 748, 818, 850, 968, 1010, 1028, 1048, 1088, 1190, 1228, 1300, 1378, 1420, 1430, 1448, 1528, 1540, 1550, 1568, 1580, 1730, 1738

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Example

2 + 3 = 5 and  4 + 9 = 13 are primes,
8 + 3 = 11 and  64 + 9 = 73 are primes.

Mathematica

Select[Prime[Range[3, 300]]-3, PrimeQ[#^2+9]&] (* Harvey P. Dale, Nov 11 2014 *)

Prog

(PARI)  {a=3; forstep(n=2, 2000, 2, if(isprime(n+a)&&isprime(n^2+a^2), print1(n", ")))}

Crossrefs

Cf. A070689, A192794.

Sequence in context: A209202 A032356 A114272 * A108468 A165593 A127219

Adjacent sequences: A193263 A193264 A193265 * A193267 A193268 A193269

Keyword

nonn

Author

Zak Seidov, Dec 19 2012

Status

approved