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A193266 Numbers n such that n + 3 and n^2 + 9 are primes. 0
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 23 06:13 EST 2020. Contains 332159 sequences. (Running on oeis4.)