
 Math Trek: More Progressive Primes, Science News Online, Aug. 28, 2004 (Site not responding. Last check: 20071107) 
  An arithmetic progression is a sequence of numbers in which each term differs from the preceding term by the same fixed amount. 
  For example, 1, 5, 9, 13, 17, and 21 is an arithmetic progression (or sequence) in which consecutive numbers differ by 4. 
  For example, 199, 409, 619, 829, 1039, 1249, 1459, 1669, 1879, 2089 is a 10term arithmetic progression in which consecutive primes differ by 210. 
 www.sciencenews.org /articles/20040828/mathtrek.asp (508 words) 
