a(n) = 2*3^n*5^(n*(n-1)/2).A218151a(n) = 2*3^n*5^(n*(n-1)/2).Terms a(0) =2a(1) =6a(2) =90a(3) =6750a(4) =2531250a(5) =4746093750External referencesoeis: A218151