对于n=2,1-(1/2+1/4+1/6)=1/12,即1/2+1%4+1/6+1/12=1,则a(2)=12。
对于n=3,1-(1/3+1/6+1/9+…+1/30)=1/42.2346。。。;
1 - (1/3 + 1/6 + 1/9 + ... + 1/30 + 1/45) = 1/687.272727...;
1-(1/3+1/6+1/9+…+1/30+1/45+1/690)=1/173880,即1/3+1/6+1/9+…+1/30+1/45+1/690+1/173880=1,因此a(3)=173880。
当n=4时,倒数之和为1/4+1/8+1/12+…+1/120+1/800+1/310824+1/66131478848+1/12922318759882631742928+1/14721162609006550046255894396208201818610800=1,则a(4)=14721162600655004625894396202011818610800。
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