A155507 Emirps with digits 1 and 9 only.

199, 991, 91199, 99119, 111119, 111919, 119191, 191911, 911111, 919111, 991999, 999199, 1191119, 1191191, 1191991, 1911911, 1991911, 9111911, 11111911, 11191991, 11911111, 11919991, 19111991, 19911191, 19919111, 19991911

Offset: 1

Author

Lekraj Beedassy, Jan 23 2009

Keywords

• nonn
• base

Comments

Subsequence of A128390.

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Crossrefs

A006567, A128390, A155508, A155509

Programs

Mathematica

emrpQ[n_]:=Module[{r=IntegerReverse[n]},r!=n&&AllTrue[{r,n},PrimeQ]]; Table[Select[FromDigits/@Tuples[{1,9},n],emrpQ],{n,8}]//Flatten (* Harvey P. Dale, Aug 09 2017 *)

Extensions

More terms from Sean A. Irvine, Apr 05 2010