12 Jul
2020
12 Jul
'20
1:33 p.m.
Kelly DeRango writes (on Twitter): <https://twitter.com/Kderango> [image: Baseball] Kelly DeRango @Kderango <https://twitter.com/Kderango> · Jul 11 <https://twitter.com/Kderango/status/1282007791041904640> Math Twitter we need your help. Our high school math club would like to find an explicit formula for the recursive relationship g[n+1] = (g[n])² - g[n] + 5. Can anyone help? The initial term is g[0] = 3. The students in question believe (and may have proved) that the sum of arctan(2/g[n]) as n goes from 0 to infinity is Pi/4, so they'd like a formula for g[n]. Jim Propp