A048405 - OEIS

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A048405

Primes with consecutive digits that differ exactly by 8.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

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

LINKS

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

EXAMPLE

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.

MATHEMATICA

Module[{nn=500, nine, one}, 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 *)

CROSSREFS

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

Sequence in context: A117315 A158473 A048420 * A110457 A320584 A209191

Adjacent sequences: A048402 A048403 A048404 * A048406 A048407 A048408

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Apr 15 1999

EXTENSIONS

Offset corrected by Sean A. Irvine, Jun 16 2021

STATUS

approved