182126domain: NAppears in sequences4-dimensional centered tetrahedral numbers.at n=30A008498G.f. A(x) satisfies: 1/(1-x) = Sum_{n>=0} x^n * (1+x)^(n*(n-1)/2) / A(x)^(n*(n+1)/2).at n=14A325579Number of unlabeled multigraphs with loops allowed and n edges covering three vertices.at n=38A327728