Hardy-Ramanujan Journal |
This paper gives a new elementary proof of the version of Siegel's theorem on L(1,χ)=∑∞n=1χ(n)n−1 for a real character χ(modk). The main result of this paper is the theorem: If 3≤k1≤k2 are integers, χ1(modk1) and χ2(modk2) are two real non-principal characters such that there exists an integer n>0 for which χ1(n)⋅χ2(n)=−1 and, moreover, if L(1,χ1)≤10−40(logk1)−1, then L(1,χ2)>10−4(logk2)−1⋅(logk1)−2k−40000L(1,χ1)2. From this the result of T. Tatuzawa on Siegel's theorem follows.