1232280

Appears in sequences

• Number of words of length 4 in the n(n-1)/2 transpositions of S[ n ] equivalent to the identity.at n=35A029699
• Number of labeled Hugenholtz diagrams with n nodes.at n=5A064732
• E.g.f.: 1/Product_{k>0} (1 - x^(2*k)/(2*k)) (even powers only).at n=5A309319
• Number of edges in a polygon whose boundary consists of n+2 equally spaced points around a semicircle and n+2 equally spaced points along the diameter (a total of 2n+2 points). See Comments for precise definition.at n=34A334459