OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
1499 is in the sequence because (1) it is a Sophie Germain prime and (2) the product of its digits 1*4*9*9=324, which is a square.
MATHEMATICA
Select[Prime[Range[1000]], PrimeQ[2#+1]&&IntegerQ[Sqrt[Times@@ IntegerDigits[ #]]]&] (* Harvey P. Dale, Dec 29 2014 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), May 07 2006
STATUS
approved