542911320domain: NAppears in sequencesNumber of sequences {s(i): i=0..n} such that |s(i)-s(i-1)|=1, i=1..n and s(i)=0 at four values of i, one of which is i=0.at n=31A052207A triangle of coefficients: T(n,m) = (2*n + 2*m + 3)! / (2*(2*m + 1)!*(2*n + 1)!).at n=34A143083Catalan transform of A135092.at n=15A146533