77189112000domain: NAppears in sequencesa(n) = core(1)*core(2)*...*core(n) where core(n) is the squarefree part of n (A007913).at n=17A069260Value of Product[k/sd(k,2),k=1..n], where sd(k,b) is the sum of the digits of k represented in base b.at n=17A109489