OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
If a(n) = 77 then we find '2'77, '5'77, '6'77, '8'77 and '9'77 to be primes.
MATHEMATICA
Select[Range[5600], Count[Table[n*10^IntegerLength[#]+#, {n, 9}], _?PrimeQ] == 5&] (* Harvey P. Dale, Apr 07 2015 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1998
STATUS
approved