a(0) = 1; for n > 0, a(n) = number of rings with n elements. 11
1, 1, 2, 2, 11, 2, 4, 2, 52, 11, 4, 2, 22, 2, 4, 4, 390, 2, 22, 2, 22, 4, 4, 2, 104, 11, 4, 59, 22, 2, 8, 2
半群非自同构数
Number of nonisomorphic semigroups of order n. +10
16
1, 1, 5, 24, 188, 1915, 28634, 1627672, 3684030417, 105978177936292
http://oeis.org/search?q=smallring&language=chineseS |