OFFSET
0,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
EXAMPLE
a(1)=21 -> 21{10}=23{9}=25{8}=30{7}=33{6}=41{5}=111{4}=210{3}=10101{2} -> 21232530334111121010101 is a prime.
MATHEMATICA
Select[Range[5000], PrimeQ[FromDigits[Flatten[Table[IntegerDigits[#, n], {n, 10, 2, -1}]]]]&] (* Harvey P. Dale, May 25 2012 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Feb 15 2000
STATUS
approved