Number of (unlabeled) 7-paths with n vertices.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =32a(6) =117a(7) =468a(8) =2151a(9) =10722a(10) =58071a(11) =333774a(12) =2018321a(13) =12678506a(14) =82035085a(15) =542520052a(16) =3646124339a(17) =24791545874a(18) =169986552195