OFFSET
1,1
COMMENTS
MATHEMATICA
Select[Range[2, 90], !PrimeQ[FromDigits[PadLeft[{1}, #, 3]]]&]-1 (* Harvey P. Dale, Jun 19 2012 *)
PROG
(PARI) is(n)=ispseudoprime((10^(n+1)-7)/3) \\ Charles R Greathouse IV, Oct 23 2013
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Lekraj Beedassy, Nov 04 2003
STATUS
approved