I recently calculated my Erdös-Bacon-Sabbath number, a geeky index that combines three metrics of connectivity: to the mathematician Paul Erdös, to the actor Kevin Bacon, and to the band Black Sabbath. To my pleasant surprise, my combined Erdös-Bacon-Sabbath number is 9: 

Erdös number, 4

I coauthored Conceptual Models of the Wind-Driven and Thermohaline Circulation with Henk Dijkstra;

Henk Dijkstra coauthored The Dynamics of a Low-Order Model for the Atlantic Multidecadal Oscillation with Henk Broer;

Henk Broer coauthored Preface [Special issue in memoriam J. G. van der Corput (1890–1975)] with Robert Tijdeman; 

Robert Tijdeman coauthored Some Diophantine Equations with Many Solutions with Paul Erdös. 

Bacon number, 3Agneepath

I appeared as an extra in Agneepath starring Amitabh Bachchan ; 

Amitabh Bachchan appeared in The Great Gatsby with Joel Edgerton; 

Joel Edgerton appeared in Black Mass with Kevin Bacon. 

Sabbath number, 2

I played in various jazz performances with Digby Fairweather during his regular visits to the Lady Mary High School, Cardiff in the early-mid 1980s; 

Digby Fairweather played as a member of The Secret Police alongside Neil Murray, a member of Black Sabbath.