Number of connected regular graphs with n nodes and girth at least 5.

Terms

a(0) =1a(1) =1a(2) =1a(3) =0a(4) =0a(5) =1a(6) =1a(7) =1a(8) =1a(9) =1a(10) =2a(11) =1a(12) =3a(13) =1a(14) =10a(15) =1a(16) =50a(17) =1a(18) =456a(19) =2a(20) =5786a(21) =9a(22) =91070a(23) =3918a(24) =1744339a(25) =4131992a(26) =163639193a(27) =4018022150a(28) =119026595851