Neil, Edwin, Leloy Thank you very much for the informations of Bernoulli Number and explanation about it. I will buy some books of BN, and I wish I will become an expert of BN. >zeta(2m) = >B_{2m} (-1)^(m+1) 2^(m2-1) pi^(m2) /(m2)!, Once I have read this equation. Yasutoshi