164745

Appears in sequences

• Expansion of e.g.f.: sech(arcsinh(x)+log(x+1))=1-4/2!*x^2+6/3!*x^3+69/4!*x^4-330/5!*x^5...at n=8A013080
• Number of singletons (strong fixed points) in pair-partitions.at n=7A233481
• The Riordan square of the double factorial of odd numbers. Triangle T(n, k), 0 <= k <= n, read by rows.at n=29A321627
• Triangle read by rows: T(n,k) is the number of linear chord diagrams on 2n vertices with one marked chord such that exactly k of the remaining n-1 chords cross the marked chord.at n=21A336598