OFFSET
1,1
EXAMPLE
11,111919,111919191919,... are all prime.
111919191919 = one copy of 11, two copies of 19, three copies of 19.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Aug 05 2005
EXTENSIONS
a(4)-a(8) from Stefan Steinerberger, Nov 17 2005
Extended by Max Alekseyev, May 20 2009
STATUS
approved