Number of connected n-regular loopless multigraphs on six unlabeled nodes.

Terms

a(0) =0a(1) =0a(2) =1a(3) =6a(4) =19a(5) =49a(6) =120a(7) =263a(8) =571a(9) =1149a(10) =2259a(11) =4218a(12) =7679a(13) =13437a(14) =22952a(15) =38013a(16) =61580a(17) =97309a(18) =150838a(19) =229045a(20) =342048a(21) =502066a(22) =726318a(23) =1035482a(24) =1457677a(25) =2026369a(26) =2785873a(27) =3788494a(28) =5101847a(29) =6805192