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

A339291

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

Terms

    a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =6a(7) =13a(8) =21a(9) =44a(10) =76a(11) =158a(12) =281a(13) =584a(14) =1067a(15) =2211a(16) =4131a(17) =8535a(18) =16231a(19) =33481a(20) =64594a(21) =133067a(22) =259821a(23) =534869a(24) =1054751a(25) =2170736a(26) =4316320a(27) =8884035a(28) =17788985a(29) =36627593

External references