A048404 Primes with consecutive digits that differ exactly by 7.

2, 3, 5, 7, 29, 181, 929, 18181, 929292929, 18181818181818181818181818181818181818181818181818181818181818181818181818181

Offset: 1

Author

Patrick De Geest, Apr 15 1999

Keywords

• nonn
• base

Comments

The next term (a(11)) has 163 digits. - Harvey P. Dale, Mar 23 2023

Links

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

Crossrefs

Cf. A048398, A048399, A048400, A048401, A048402, A048403, A048405, A048409.

Programs

Mathematica

Module[{s18,s81,s29,s92},s18=Select[Table[FromDigits[PadRight[{},n,{1,8}]],{n,1,181,2}],PrimeQ]; s81=Select[Table[FromDigits[PadRight[{},n,{8,1}]],{n,2,182,2}],PrimeQ];s29 = Select[ Table[FromDigits[PadRight[{},n,{2,9}]],{n,2,182,2}],PrimeQ]; s92 =Select[Table[ FromDigits[ PadRight[{},n,{9,2}]],{n,1,183,2}],PrimeQ]; Join[{2,3,5,7},s18,s81,s29,s92]//Sort] (* Harvey P. Dale, Mar 23 2023 *)