Number of rings with 1 containing n elements.

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =1a(5) =1a(6) =1a(7) =11a(8) =4a(9) =1a(10) =1a(11) =4a(12) =1a(13) =1a(14) =1a(15) =50a(16) =1a(17) =4a(18) =1a(19) =4a(20) =1a(21) =1a(22) =1a(23) =11a(24) =4a(25) =1a(26) =12a(27) =4a(28) =1a(29) =1