A120821 a(n) consecutive digits ascending beginning with the digit 3 give a prime.

1, 179, 529, 62625

Offset: 1

Author

Robert G. Wilson v, Jul 05 2006

Keywords

• nonn
• base
• hard
• more

Comments

Digits are in ascending order beginning with 3 and after 9 comes 0.

The sequence "a(n) consecutive digits descending beginning with the digit 3 give a prime." has only one term, 1 which represents the prime 3.

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

Crossrefs

Cf. A006055, A120819, A120820, A120822, A120823, A120824, A120825, A120826, A120827.

Programs

Mathematica

fQ[n_] := PrimeQ@ FromDigits@ Mod[2+Range@n, 10]; lst = {}; Do[ If[fQ@n, AppendTo[lst, n]; Print@n], {n, 10000}]; lst

Extensions

a(4) from Michael S. Branicky, Apr 03 2025