Number of unlabeled loop-graphs covering n vertices with at most n edges.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =19a(5) =48a(6) =135a(7) =373a(8) =1085a(9) =3184a(10) =9590a(11) =29258a(12) =90833a(13) =285352a(14) =908006a(15) =2919953a(16) =9487330a(17) =31111997a(18) =102934602a(19) =343389708a(20) =1154684849a(21) =3912345408a(22) =13353796977a(23) =45906197103a(24) =158915480378a(25) =553897148543