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A048405 Primes with consecutive digits that differ exactly by 8. 12

%I #16 Jan 04 2023 21:02:31

%S 2,3,5,7,19,191,919,919191919,91919191919,91919191919191919,

%T 91919191919191919191919,191919191919191919191919191919191

%N Primes with consecutive digits that differ exactly by 8.

%C The next term (a(13)) has 133 digits. - _Harvey P. Dale_, Jan 04 2023

%H Sean A. Irvine, <a href="/A048405/b048405.txt">Table of n, a(n) for n = 1..13</a>

%e 2 is a term since all its consecutive digits differ by 5 (there aren't any).

%e 19 is a term because 1 and 9 differ by 8.

%e 23 is not a term because its consecutive digits differ only by 1.

%t Module[{nn=500,nine,one},one=Select[Table[FromDigits[PadRight[{},n,{1,9}]],{n,nn}],PrimeQ];nine=Select[Table[FromDigits[PadRight[{},n,{9,1}]],{n,nn}],PrimeQ];Sort[Join[{2,3,5,7},nine,one]]] (* _Harvey P. Dale_, Jan 04 2023 *)

%Y Cf. A048398, A048399, A048400, A048401, A048402, A048403, A048404, A048410.

%K nonn,base

%O 1,1

%A _Patrick De Geest_, Apr 15 1999

%E Offset corrected by _Sean A. Irvine_, Jun 16 2021

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Last modified March 28 17:25 EDT 2024. Contains 371254 sequences. (Running on oeis4.)