OFFSET
1,1
EXAMPLE
For p=3, 19^3-18=6841; p=5, 19^5-18=2476081; p=7, 19^7-18=893871721
PROG
(Magma) [ p: p in PrimesUpTo(2000)| IsPrime(19^p-18)]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Mar 14 2010
STATUS
approved