OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Prime[Range[250]], MemberQ[{1, 9}, Max[Join[IntegerDigits[ #], IntegerDigits[ Prime[#]]]]]&] (* Harvey P. Dale, Feb 08 2022 *)
PROG
(PARI) isok(p) = isprime(p) && (vecmax(digits(eval(concat(Str(p), Str(prime(p)))))) == 9); \\ Michel Marcus, Feb 18 2021
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
Juri-Stepan Gerasimov, Jan 20 2009
EXTENSIONS
Entries checked by R. J. Mathar, May 10 2010
STATUS
approved