OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
a(2)=577 is a term because all digits are equal to 7 except one.
MATHEMATICA
Select[Union[FromDigits/@(Flatten[Permutations/@Flatten[ Table[ PadRight[ {n}, i, 7], {n, 9}, {i, 3, 6}], 1], 1])], PrimeQ] (* Harvey P. Dale, Dec 12 2015 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, Apr 29 2005
STATUS
approved