453457

Appears in sequences

• Number of permutations P of {1,2,...,n} such that P(1)=1 and |P^-1(i+1)-P^-1(i)| equals 1 or 2 for i=1,2,...,n-1.at n=33A038718
• Positions of the integers in the ordering of rational numbers as generated by the rules: 1 is in S, and if nonzero x is in S, then x+1 and -1/x are in S. (See Comments.)at n=43A226137
• G.f. A(x) satisfies A(x) = 1/(1 - x/(1 - x*A(x)^2)^4).at n=8A391647