A120826 a(n) consecutive digits ascending beginning with the digit 8 give a prime.

2, 82, 152, 7066, 84892

Offset: 1

Author

Robert G. Wilson v, Jul 05 2006

Keywords

• nonn
• base
• hard
• more

Comments

Digits are in ascending order beginning with 8 and after 9 comes 0.

The sequence "a(n) consecutive digits descending beginning with the digit 8 give a prime" has no terms.

a(6) > 10^5. - Michael S. Branicky, Apr 11 2025

Examples

			2 is a term since 89 is a prime.
82 is a term because 8901234567890123456789012345678901234567890123456789012345678901234567890123456789 is a prime.
		

Crossrefs

Cf. A006055, A120819, A120820, A120821, A120822, A120823, A120824, A120825, A120827.

Programs

Mathematica

fQ[n_] := PrimeQ@ FromDigits@ Mod[7+Range@n, 10]; lst = {}; Do[ If[fQ@n, AppendTo[lst, n]; Print@n], {n, 5000}]; lst

Extensions

a(4) from Bert Dobbelaere, Apr 01 2025

a(5) from Michael S. Branicky, Apr 03 2025