A120823 a(n) consecutive digits ascending beginning with the digit 5 give a prime..

1, 29, 269, 689

Offset: 1

Author

Robert G. Wilson v, Jul 05 2006

Keywords

• nonn
• base
• hard
• more

Comments

Digits are in ascending order beginning with 5 and after 9 comes 0.

The sequence "a(n) consecutive digits descending beginning with the digit 5 give a prime." has only one term, 1 which represents the prime 5.

a(5) > 10^5. - Michael S. Branicky, Apr 08 2025

Examples

			29 is a term since the 29-digit number 56789012345678901234567890123 is a prime.
		

Crossrefs

Cf. A006055, A120819, A120820, A120821, A120822, A120824, A120825, A120826, A120827.

Programs

Mathematica

fQ[n_] := PrimeQ@ FromDigits@ Mod[4+Range@n, 10]; lst = {}; Do[ If[fQ@n, AppendTo[lst, n]; Print@n], {n, 9000}]; lst