165297834

Appears in sequences

• a(n) = 2*3^n*(2*n)!/(n!*(n+2)!).at n=10A000168
• Expansion of g.f. c(3x)^4, where c(x) is the g.f. of A000108.at n=8A101602
• Triangle T(n,k) read by rows: T(n,k) is the number of rooted genus-k maps with n edges, n>=0, 0<=k<=n.at n=55A238396
• Triangle read by rows: T(n,g) is the number of rooted maps with n edges on an orientable surface of genus g.at n=30A269919