Number of connected regular graphs with n nodes and girth at least 6.

Terms

a(0) =1a(1) =1a(2) =1a(3) =0a(4) =0a(5) =0a(6) =1a(7) =1a(8) =1a(9) =1a(10) =1a(11) =1a(12) =1a(13) =1a(14) =2a(15) =1a(16) =2a(17) =1a(18) =6a(19) =1a(20) =33a(21) =1a(22) =386a(23) =1a(24) =7575a(25) =1a(26) =181229a(27) =1a(28) =4624503a(29) =1