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

A339294

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

Terms

    a(0) =0a(1) =1a(2) =1a(3) =2a(4) =5a(5) =13a(6) =35a(7) =101a(8) =299a(9) =916a(10) =2859a(11) =9087a(12) =29247a(13) =95188a(14) =312490a(15) =1033715a(16) =3441280a(17) =11520726a(18) =38758234a(19) =130962986a(20) =444251957a(21) =1512321767a(22) =5164750890a(23) =17689837577a(24) =60752024243a(25) =209154519704a(26) =721707099632

External references