A099667 a(n) is the largest prime before A002281(n); repdigits repeating 7.

5, 73, 773, 7759, 77773, 777769, 7777769, 77777761, 777777773, 7777777741, 77777777767, 777777777773, 7777777777771, 77777777777753, 777777777777773, 7777777777777753, 77777777777777747, 777777777777777743

Offset

1,1

Links

Michael De Vlieger, Table of n, a(n) for n = 1..1000

Example

n=2: 73 is before 77.

Mathematica

Table[NextPrime[7 (10^n - 1)/9, -1], {n, 35}]
(* Second program: *)
Rest[NextPrime[#, -1]&/@LinearRecurrence[{11, -10}, {0, 7}, 25]] (* Harvey P. Dale, May 24 2015 *)

Crossrefs

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

Sequence in context: A070530 A248046 A059017 * A108444 A155662 A182328

Adjacent sequences: A099664 A099665 A099666 * A099668 A099669 A099670

Keyword

base,nonn

Author

Labos Elemer, Nov 17 2004

Extensions

Name changed by David A. Corneth, Sep 01 2017

Status

approved