OFFSET
1,1
LINKS
Jinyuan Wang, Table of n, a(n) for n = 1..500
MATHEMATICA
Table[SelectFirst[FromDigits/@Tuples[{1, 5}, n], PrimeQ], {n, 20}] (* Harvey P. Dale, Aug 04 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jan 04 1999
EXTENSIONS
Corrected by Harvey P. Dale, Mar 19 2013
STATUS
approved