|   | 1 |  initial version  | 
From the documentation at http://doc.sagemath.org/html/en/reference/interfaces/sage/interfaces/r.html, it looks like the tilde operator is not recognized. So, I think you need the following:
a =  r.lm(LLCCS00.tilde(OILBRNP), data = reader)
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                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.