493350

Appears in sequences

• a(n) = 2*binomial(3*n-3, n-1)/(2*n-1) for n >= 2, and a(1) = 1.at n=9A046646
• Triangle of rooted planar maps.at n=54A046651
• If n mod 2 = 0 then m := n/2 and a(n) = (3*m)!*(5*m+1)/((m+1)!*(2*m+1)!); otherwise m := (n-1)/2, a(n) = 6*(3*m+2)!/(m!*(2*m+3)!).at n=17A047750
• Triangle read by rows: T(n,k) is the number of nonseparable planar maps with r*n edges and a fixed outer face of r*k edges which are invariant under a rotation of 1/r for any r >= 2 (independent of actual value of r).at n=45A091599
• Seventh column (m=6) of (1,4)-Pascal triangle A095666.at n=21A095669
• Triangle read by rows: T(n,k) is the number of noncrossing trees with n edges in which the leftmost child of the root has degree k.at n=46A101401
• G.f. satisfies: A(x) = x/series_reversion(x/G(x)) where A(x) + A(-x) = 2*G(x^2) and G(x) is the g.f. of A046646.at n=18A116637
• a(n)=3!*n!/(8!*19!).at n=2A157983
• Numbers k such that 2^k + 1 is divisible by the sum of its decimal digits.at n=28A333474