A099664 a[n] is the largest prime before A002278[n] repdigits.

3, 43, 443, 4441, 44417, 444443, 4444409, 44444399, 444444443, 4444444429, 44444444441, 444444444443, 4444444444439, 44444444444353, 444444444444421, 4444444444444423, 44444444444444411, 444444444444444419

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

n=2: 43 is before 44.

Mathematica

<<NumberTheory`NumberTheoryFunctions` Table[Table[PreviousPrime[4*(10^n-1)/9], {n, 1, 35}]
Table[NextPrime[FromDigits[PadRight[{}, n, 4]], -1], {n, 20}] (* Harvey P. Dale, Feb 25 2013 *)

Crossrefs

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Sequence in context: A020461 A138974 A036940 * A173770 A093163 A199020

Adjacent sequences: A099661 A099662 A099663 * A099665 A099666 A099667

Keyword

base,nonn

Author

Labos Elemer, Nov 17 2004

Status

approved