147048

Appears in sequences

• Series for second parallel moment of square lattice (eventually changes sign).at n=10A006729
• a(n) = sum_{k=1..n} prime(k)*prime(k+1).at n=30A074745
• G.f.: exp( Sum_{n>=1} A020696(n)/2 * x^n/n ), where A020696(n) = Product_{d|n} (d + 1).at n=22A299437
• Let PG(n) be the graph with one node for each free n-celled polycube, and edges between nodes corresponding to polycubes that can be obtained from each other by moving one cell, where the intermediate polyform (the set of cells remaining when the cell to be moved is detached) is not required to be a connected polycube. a(n) is the number of edges in PG(n).at n=7A390205