A099665 a[n] is the largest prime before A002279[n] repdigits.

3, 53, 547, 5531, 55547, 555523, 5555527, 55555553, 555555541, 5555555519, 55555555543, 555555555551, 5555555555551, 55555555555541, 555555555555529, 5555555555555539, 55555555555555519, 555555555555555487

Offset

1,1

Links

Table of n, a(n) for n=1..18.

Example

n=2: 53 is before 55.

Mathematica

<<NumberTheory`NumberTheoryFunctions` Table[Table[PreviousPrime[5*(10^n-1)/9], {n, 1, 35}]
NextPrime[#, -1]&/@Table[FromDigits[PadRight[{}, n, 5]], {n, 20}] (* Harvey P. Dale, Aug 31 2015 *)

Crossrefs

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

Sequence in context: A036941 A215435 A121504 * A173802 A001279 A092447

Adjacent sequences: A099662 A099663 A099664 * A099666 A099667 A099668

Keyword

base,nonn

Author

Labos Elemer, Nov 17 2004

Status

approved