271104

Appears in sequences

• a(n) = A027144(2n, n).at n=8A027145
• a(n) = A027144(n, floor(n/2)).at n=16A027150
• Number of n-th order connected Feynman diagrams.at n=4A214298
• Triangle d_k(n) read by rows: number of n-th order Feynman diagrams with k interactions, 0<=k<=n.at n=14A214299