595448domain: NAppears in sequencesa(n) = Sum_{k=1..n-1} k^3*sigma(k)*sigma(n-k).at n=13A000499Molecular topological indices of the n X n grid graphs.at n=10A192828Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with meet {{1},...,{n}} and join of length k.at n=30A318389