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

A339288

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

Terms

    a(0) =0a(1) =1a(2) =1a(3) =3a(4) =8a(5) =22a(6) =64a(7) =189a(8) =577a(9) =1788a(10) =5642a(11) =18016a(12) =58213a(13) =189792a(14) =623913a(15) =2065219a(16) =6878429a(17) =23032917a(18) =77500237a(19) =261892491a(20) =888439320a(21) =3024510467a(22) =10329241959a(23) =35379140285a(24) =121502993735a(25) =418306868672

External references