Number of essentially series oriented series-parallel networks with n elements and without unit elements in parallel.

A339154

Number of essentially series oriented series-parallel networks with n elements and without unit elements in parallel.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =1a(4) =3a(5) =6a(6) =14a(7) =30a(8) =70a(9) =165a(10) =397a(11) =961a(12) =2368a(13) =5875a(14) =14722a(15) =37134a(16) =94312a(17) =240823a(18) =618147a(19) =1593606a(20) =4125218a(21) =10717064a(22) =27934867a(23) =73032798a(24) =191464677a(25) =503218042a(26) =1325678981a(27) =3499913710a(28) =9258627528a(29) =24538328431

External references