Shifted Dirichlet series - MathOverflow most recent 30 from http://mathoverflow.net2013-05-22T23:23:50Zhttp://mathoverflow.net/feeds/question/6450http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/6450/shifted-dirichlet-seriesShifted Dirichlet seriesDan Brumleve2009-11-22T09:52:40Z2009-11-22T11:15:52Z
<p>If $\sum_{n=1}^\infty \frac{a_n}{n^s} $ converges, does
$\sum_{n=1}^\infty \frac{a_n}{(n+1)^s} $ also converge?</p>
http://mathoverflow.net/questions/6450/shifted-dirichlet-series/6454#6454Answer by engelbrekt for Shifted Dirichlet seriesengelbrekt2009-11-22T11:15:52Z2009-11-22T11:15:52Z<p>Yes, because $(n+1)^{-s} = n^{-s} + sn^{-s-1} + O(|s|^2n^{-\sigma - 2})$. The first series necessarily converges in the open half-plane strictly to the right of s, and converges absolutely in the half-plane strictly to the right of s + 1. I hope I am not doing homework from a course in analytic number theory here.</p>