OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1001 [offset shifted by Georg Fischer, Oct 14 2019]
EXAMPLE
199 = (1)(9)(9) -> (1)(81)(81) = 18181 which is a prime.
MATHEMATICA
Select[Range[400], PrimeQ[FromDigits[Flatten[IntegerDigits/@ (IntegerDigits[ #]^2)]]]&] (* Harvey P. Dale, Oct 13 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Mar 15 1999
STATUS
approved