Lambert Klasen wrote: > 10350794431055162386718619237468234569 > 7923871097285295625344647665764672671 > 383725126655170964501315730676446647 > are really prime ? > afaik they are stong pseudoprimes, For such tiny primes, Pari can make a "p-1" certificate faster than you can blink. Use the isprime function. -- Don Reble djr at nk.ca