Number of essentially parallel unoriented series-parallel networks with n elements.

A339224

Number of essentially parallel unoriented series-parallel networks with n elements.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =41a(6) =132a(7) =470a(8) =1730a(9) =6649a(10) =26122a(11) =104814a(12) =426257a(13) =1754055a(14) =7282630a(15) =30470129a(16) =128304158a(17) =543303752a(18) =2311904374a(19) =9880776407a(20) =42394198909a(21) =182537610058a(22) =788473887942

External references