30419domain: NAppears in sequencesa(n) = 20*n^2 - 1.at n=38A158491Number of zero-sum -n..n arrays of 4 elements with adjacent element differences also in -n..n.at n=24A202254a(n) = Sum_{k=0..n} binomial(n,2*k)*binomial(2*k,k)/(2*k-1).at n=13A295112