OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
MATHEMATICA
lpss[n_]:=Module[{idn7=IntegerDigits[7^n]}, Max[Select[Flatten[ Table[ FromDigits/@ Partition[idn7, i, 1], {i, Length[idn7]}]], PrimeQ]]]; Array[ lpss, 25, 0]/.-\[Infinity]->0 (* Harvey P. Dale, Aug 17 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick De Geest, Jun 15 1998
STATUS
approved