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A032621 Numbers n such that n concatenated with n + 6 is a prime. 1

%I

%S 1,11,13,17,25,31,35,43,65,71,83,95,97,101,125,127,137,151,155,157,

%T 161,163,167,187,197,203,205,211,217,221,223,227,233,235,245,251,257,

%U 263,265,271,283,317,331,335,337,341,353,355,373,385,391,401,427,433

%N Numbers n such that n concatenated with n + 6 is a prime.

%t Select[Range[1,501,2],PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ #+6]]]]&] (* _Harvey P. Dale_, Nov 17 2013 *)

%Y Cf. A032611.

%K nonn,base

%O 1,2

%A _Patrick De Geest_, May 15 1998

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Last modified May 31 19:40 EDT 2020. Contains 334748 sequences. (Running on oeis4.)