a(n)=sum_{k=1..n}(LCM(n,n-1,...,n-k+2,n-k+1)/LCM(1,2,...,k)). 1, 3, 7, 13, 31, 38, 113, 165, 265, 420, 1607, 1004, 3979, 6893, 4205, 8665, 40903
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