69886

Appears in sequences

• Number of achiral planar maps with n edges.at n=9A006443
• Duplicate of A006443.at n=8A054936
• Star of David bonding digraph: characteristic polynomial: x(-18 - 10 x + 147 x^2 + 71 x^3 - 312 x^4 - 221 x^5 + 140 x^6 + 121 x^7 - 17 x^8 - 21 x^9 + x^11).at n=6A121962
• G.f.: A(x) = F(x*G(x))^2 where F(x) = G(x*F(x)) = 1 + x*F(x)^3 is the g.f. of A001764 and G(x) = F(x/G(x)) = 1 + x*G(x)^2 is the g.f. of A000108 (Catalan).at n=7A153390
• Triangle read by rows: T(n,k) is the number of achiral combinatorial maps with n edges and genus k, 0 <= k <= floor(n/2).at n=25A380234