%I #18 Mar 09 2023 20:03:59

%S 0,1,75,9345,1865745,554479695,231052877055,128938132548225,

%T 92986310399407425,84250567868935042575,93744545254140599193375,

%U 125717783386887888296925825,200041202339679732328342670625,372688996228146502285257581079375,803768398459351988653830600415029375

%N Number of rank n+1 simple connected series-parallel matroids on [2n].

%H Luis Ferroni and Matt Larson, <a href="https://arxiv.org/abs/2303.02253">Kazhdan-Lusztig polynomials of braid matroids</a>, arXiv:2303.02253 [math.CO], 2023.

%e For n=2 the a(2) = 1 rank 3 simple connected series-parallel matroid on [4] is the uniform matroid of rank 3.

%o (PARI) a(n) = T(2*n)[2*n][n+1] \\ T(n) defined in A361355. - _Andrew Howroyd_, Mar 09 2023

%Y Cf. A034941, A361355.

%K nonn

%O 1,3

%A _Matt Larson_, Mar 06 2023

%E Terms a(10)-a(15) from _Andrew Howroyd_, Mar 09 2023