A120823 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A120823

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

1, 29, 269, 689

(list; graph; refs; listen; history; text; internal format)

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