46670

Appears in sequences

• Triangle read by rows: T(n,k) is the number of hill-free Schroeder paths of length 2n that have k weak ascents (1<=k<=n-1 for n>=2; k=1 for n=1). A Schroeder path of length 2n is a lattice path from (0,0) to (2n,0) consisting of U=(1,1), D=(1,-1) and H=(2,0) steps and never going below the x-axis. A hill is a peak at height 1. A weak ascent in a Schroeder path is a maximal sequence of consecutive U and H steps.at n=42A114691
• Numbers n such that if x=sigma(n)-tau(n)-n then n=sigma(x)-tau(x)-x.at n=28A238227
• Number of length-n binary strings s whose longest repeated suffix appears exactly twice in s.at n=15A284462
• Number of compositions (ordered partitions) of n into distinct parts, the least being 4.at n=50A339165
• a(n) = Sum_{k=0..n} (-1)^k * binomial(n+k-1,n-k) * Fibonacci(k+1).at n=17A390850