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A069678 Primes with either no internal digits or all internal digits are 3. 9

%I #15 Jan 26 2023 15:08:04

%S 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,

%T 97,131,137,139,233,239,331,337,431,433,439,631,733,739,839,937,2333,

%U 2339,3331,4337,4339,5333,6337,7331,7333,9337,13331,13337,13339,23333,23339

%N Primes with either no internal digits or all internal digits are 3.

%H Harvey P. Dale, <a href="/A069678/b069678.txt">Table of n, a(n) for n = 1..267</a>

%t Join[Prime[Range[25]],Select[Flatten[Table[10FromDigits[PadRight[{n},k,3]]+d,{n,9},{d,{1,3,7,9}},{k,2,5}]],PrimeQ]]//Sort (* _Harvey P. Dale_, Aug 08 2020 *)

%Y Cf. A069675, A069676, A069677, A069679, A069680, A069681, A069682, A069683, A069684.

%K nonn,base

%O 1,1

%A _Amarnath Murthy_, Apr 06 2002

%E Offset corrected and name changed by _Arkadiusz Wesolowski_, Sep 07 2011

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Last modified April 23 12:59 EDT 2024. Contains 371913 sequences. (Running on oeis4.)