125476
domain: N
Appears in sequences
- a(n) = C(1,1) + C(3,2) + C(5,3) + ... + C(2*n-1,n).at n=9A079309
- Fourth row of Pascal-(1,2,1) array A081577.at n=14A081584
- Triangle read by rows: T(n,k) is the number of Schroeder paths of length 2n and having k horizontal segments (a horizontal segment is a maximal string of horizontal steps).at n=41A104549
- a(n) = 4*a(n-1)-4*a(n-3)-a(n-4).at n=9A107382
- Expansion of (1+2x-sqrt(1-4x^2))/(2(1-x^2)*sqrt(1-4x^2)).at n=20A174783
- Number of base pyramids in all length n left factors of Dyck paths.at n=20A191790
- Number of (w,x,y,z) with all terms in {1,...,n} and w<x+y+z.at n=19A212090
- Zeroless numbers n such that n and n^2 have the same set of decimal digits.at n=24A257763
- a(n) = Sum_{k=1..n-1} ((-1)^(k+n+1)*binomial(k,floor(k/2))).at n=20A332754
- Number of nonempty subsets of {1..n} with median n/2.at n=20A361801
- Number of nonempty subsets of {1..n} with median n/2.at n=21A361801