25662825

Appears in sequences

• a(n) = 3*(2*n)!/((n+2)!*(n-1)!).at n=15A000245
• a(n) = T(n, floor(n/2)), where T = Catalan triangle (A008315).at n=29A026008
• a(n) = 3*binomial(2n, n-1)/(n+2), n > 0, with a(0)=1.at n=15A071724
• Isomers of polyenes attached to benzene (see Cyvin et al. for precise definition).at n=29A121094
• Row sums of the inverse of number triangle A(n,k) = 1/C(n) if k <= n <= 2k, 0 otherwise, where C(n) = A000108(n).at n=16A127768
• a(n) = 3*C(4*n-2,2*n)/(2*n+1) - 2*0^n.at n=8A127769
• Lexicographically earliest sequence of distinct positive integers with no finite subset summing to a Catalan number (A000108).at n=41A353983
• Arises from enumeration of a certain class of partial zig-zag knight's paths on the square grid.at n=29A368379