56410

Appears in sequences

• One-half the number of permutations of length n with exactly 2 rising or falling successions.at n=9A000349
• Triangle read by rows: T(n,k) is one-half the number of permutations of length n with exactly n-k rising or falling successions, for n >= 1, 1 <= k <= n. T(1,1) = 1 by convention.at n=42A010028
• Triangle read by rows: T(n,k) = one-half number of permutations of length n with exactly k rising or falling successions, for n >= 1, 0 <= k <= n-1. T(1,0) = 1 by convention.at n=38A086856
• a(1)=1. a(n) = a(n-1) + (sum of terms, from among terms a(1) through a(n-1), which are prime or 1).at n=21A104589
• G.f. A(x,y) satisfies: A( x - y*A(x,y)^2, y) = x + (1-y)*A(x,y)^2, where the coefficients T(n,k) of x^n*y^k form a triangle read by rows n>=1, for k=0..n-1.at n=31A277295
• Central terms of triangle A277295 in even-indexed rows; a(n) = A277295(2*n,n-1).at n=3A277299