Wikipedia: The Erdos number, honouring the late Hungarian mathematician Paul Erdos, one of the most prolific writers of mathematical papers, is a way of describing the "collaborative distance", in regard to mathematical papers, between an author and Erdos. In order to be assigned an Erdos number, an author must co-write a mathematical paper with an author with a finite Erdos number. Paul Erdos has an Erdos number of zero. If the lowest Erdos number of a coauthor is X, then the author's Erdos number is X + 1.

You can read more about the Erdos Number project here.

My Erdos Number is 3 through the following collaboration chain:

Paul Erdos Þ Patrick O' Neil Þ Krithi Ramamritham Þ Aameek Singh

Following are the corresponding publications:

Paul Erdos and Patrick O'Neil, "On a generalization of Ramsey Numbers", Discrete Mathematics, Vol-4(1), Jan 1973, pp. 29-35.
Patrick O'Neil, Krithi Ramamritham and Calton Pu, "A Two-Phase Approach to Predictably Scheduling Real-Time Transactions", Performance of Concurrency Control: Mechanisms in Centralized Database Systems, V. Kumar (ed.), Prentice-Hall, Sep 1995, pp. 494-522.
Aameek Singh, Abhishek Trivedi, Krithi Ramamritham and Prashant Shenoy, "PTC : Proxies that Transcode and Cache in Heterogeneous Web Client Environments", World Wide Web Journal, Vol-7(1), 2004.