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%I #41 Sep 08 2022 08:46:13
%S 11,13,29,53,67,71,89,101,103,137,191,193,227,229,233,269,281,359,431,
%T 449,461,463,499,569,593,641,643,659,683,701,719,769,821,823,857,859,
%U 877,967,1019,1061,1091,1093,1223,1289,1439,1451,1487,1489,1579,1597,1601,1619
%N Prime numbers that sum to a prime when added to their digital root.
%F (a(n) mod 9) mod 2 = 0. - _Altug Alkan_, Sep 28 2015
%e 11 (prime) + 2 (its digital root) = 13 (prime);
%e 89 (prime) + 8 (its digital root) = 97 (prime).
%t Select[Prime[Range[300]], PrimeQ[# + Mod[#, 9]] &] (* _Vincenzo Librandi_, Sep 29 2015 *)
%o (PARI) lista(nn) = forprime(p=2, nn, if (isprime(p + p%9), print1(p, ", "))); \\ _Michel Marcus_, Sep 12 2015
%o (Magma) [p: p in PrimesUpTo(2000) | IsPrime(p+(p mod 9))]; // _Vincenzo Librandi_, Sep 29 2015
%Y Cf. A000040, A010888, A038194.
%K nonn,base
%O 1,1
%A _Gary Croft_, Sep 11 2015
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