A120823 Number of digits of the smallest prime with n consecutive ascending digits and most significant digit a five.

1, 29, 269, 689

Offset

1,2

Comments

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

The sequence "Primes with n consecutive digits descending beginning with the digit five" has only one term, 1 which represents the prime 5.

Links

Table of n, a(n) for n=1..4.

Example

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

Mathematica

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

Crossrefs

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

Sequence in context: A224157 A223776 A224408 * A186263 A110692 A081684

Adjacent sequences: A120820 A120821 A120822 * A120824 A120825 A120826

Keyword

base,hard,nonn

Author

Robert G. Wilson v, Jul 05 2006

Status

approved