298932domain: NAppears in sequencesRelated to coefficient of m in Jacobi elliptic function cn(z, m).at n=7A0027541 + Sum_{n >= 1} Sum_{k = 0..n-1} (-1)^n*T(n,k)*y^(2*k)*x^(2*n)/(2*n)! = JacobiCN(x,y).at n=22A060627Convolution of 3^n and floor(n/2).at n=13A097137