1277788

Appears in sequences

• a(n) = 2*Catalan(n) - Catalan(n-1).at n=12A000782
• Number of unrooted triangulations with reflection symmetry of a disk with one internal node and n+3 nodes on the boundary.at n=24A005508
• a(n) = (7*n+2)*C(n)/(n+2), where C(n) is the n-th Catalan number.at n=11A061557
• Numbers k such that sigma(k) = phi(k)*omega(k).at n=33A073567