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

A339295

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

Terms

    a(0) =1a(1) =0a(2) =1a(3) =2a(4) =4a(5) =10a(6) =25a(7) =69a(8) =197a(9) =589a(10) =1806a(11) =5685a(12) =18168a(13) =58905a(14) =192904a(15) =637294a(16) =2119994a(17) =7094961a(18) =23865782a(19) =80642017a(20) =273571625a(21) =931389949a(22) =3181184007a(23) =10897272983a(24) =37429033777a(25) =128874546753a(26) =444744161951

External references