Number of commutative rings with n elements.

Terms

a(0) =1a(1) =2a(2) =2a(3) =9a(4) =2a(5) =4a(6) =2a(7) =34a(8) =9a(9) =4a(10) =2a(11) =18a(12) =2a(13) =4a(14) =4a(15) =162a(16) =2a(17) =18a(18) =2a(19) =18a(20) =4a(21) =4a(22) =2a(23) =68a(24) =9a(25) =4a(26) =36a(27) =18a(28) =2a(29) =8