Format (cm)         (inch)   400dpi    300dpi   200dpi

A0  1189mm x 841mm
A1  841mm x 596mm
A2  596mm x 420mm
A3  420mm x 297mm
A4  297mm x 210mm
A5  210mm x 297mm
A6  148mm x 210mm
A7  105mm x 74mm

An  (1189 mm / 2^(n/2) ) x 1189 mm / 2^((n+1)/2)
An   1189 mm / 1.4142^n  x 1189 mm / 1.4142^(n+1)
An   1189 mm * 0.7071^n  x 1189 mm / 0.7071^(n+1)