A048405 Primes with consecutive digits that differ exactly by 8.

2, 3, 5, 7, 19, 191, 919, 919191919, 91919191919, 91919191919191919, 91919191919191919191919, 191919191919191919191919191919191

Offset: 1

Author

Patrick De Geest, Apr 15 1999

Keywords

• nonn
• base

Comments

The next term (a(13)) has 133 digits. - Harvey P. Dale, Jan 04 2023

Examples

			2 is a term since all its consecutive digits differ by 5 (there aren't any).
19 is a term because 1 and 9 differ by 8.
23 is not a term because its consecutive digits differ only by 1.
		

Links

• Sean A. Irvine, Table of n, a(n) for n = 1..13

Crossrefs

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

Programs

Mathematica

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 *)

Extensions

Offset corrected by Sean A. Irvine, Jun 16 2021