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 A192638 Numbers n such that 4n + 3 and 16n + 15 are prime. 0
 1, 2, 4, 7, 11, 14, 16, 26, 37, 44, 56, 67, 76, 82, 89, 91, 109, 116, 121, 124, 142, 146, 149, 161, 172, 179, 209, 226, 247, 254, 257, 259, 296, 314, 319, 322, 326, 329, 341, 356, 361, 362, 364, 377, 391, 392, 436, 439, 446, 452, 467, 482, 494, 496 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Infinite under Dickson's conjecture. [Charles R Greathouse IV, Jul 06 2011] No n can be a multiple of 3. If it is 1 mod 3, it cannot end in 3 or 8.  If it is 2 mod 3, it cannot end in 1 or 6.  One can see the potential of iterative chains producing primes. LINKS EXAMPLE For n=37, 4*37+3=151 and 16*37+15=607. MATHEMATICA Select[Range[500], PrimeQ[4# + 3] && PrimeQ[16# + 15] &] (* Alonso del Arte, Jul 06 2011 *) PROG (PARI) for(n=1, 1e3, if(isprime(4*n+3)&&isprime(16*n+15), print1(n", "))) \\ Charles R Greathouse IV, Jul 06 2011 CROSSREFS Cf. A002145. Sequence in context: A086795 A064690 A138766 * A211372 A054850 A225154 Adjacent sequences:  A192635 A192636 A192637 * A192639 A192640 A192641 KEYWORD nonn AUTHOR J. M. Bergot, Jul 06 2011 STATUS approved

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Last modified May 26 10:17 EDT 2022. Contains 354086 sequences. (Running on oeis4.)