Gnevyshev-Ohl rule

The Gnevyshev-Ohl rule is an empirical rule according to which the sum of sunspot numbers over an odd cycle exceeds that of the preceding even cycle.

See Gnevishev M.N., Ohl A.I., 1948: About 22-year cycle of solar activity. Astronomical Journal. V.25, 18-20 (in Russian).

The rule breaks down under certain conditions. (See Komitov, B., Bonev, B. "AMPLITUDE VARIATIONS OF THE 11 YEAR CYCLE AND THE CURRENT SOLAR MAXIMUM 23", The Astrophysical Journal, 554:L000–L000, 2001 June 10)