Summation Formulae Table

*To*: mathgroup at smc.vnet.net*Subject*: [mg28431] Summation Formulae Table*From*: O D <O_member at newsranger.com>*Date*: Wed, 18 Apr 2001 03:23:35 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Is there a way to access the tables that Sum[] uses to simplify summations into known functions like for example Sum[Exp[-a* n^2], {n, -Infinity, Infinity}] is simplified into EllipticTheta[3, 0, E^(-a)] Is there a way to use the table in reverse, to approximate a known function? I am not interested in the above example, so please do not tell me how I can approximate EllipticTheta[]... I am a rather naive Mathematica user, so please be explicit. Thank you. O