153730domain: NAppears in sequencesa(n) = -Floor[n/2]! + Sum[(Eulerian[n - j, j]), {j, 0, Floor[n/2]}].at n=11A174993Number of (w,x,y,z) with all terms in {0,...,n} and |w-x|=max{w,x,y,z}-min{w,x,y,z}.at n=29A212755G.f.: Sum_{n>=0} x^n * Sum_{k=0..n} binomial(n,k)^2 * x^k/(1-x)^k.at n=13A217661