675/225=3
225/90=5/2
90/45=2
45/30=3/2
30/30=1
30/()=1/2 =>()=60
675/225=3
225/90=5/2
90/45=2
45/30=3/2
30/30=1
30/()=1/2 =>()=60
a(n)/a(n+1)=3-(n-1)/2
a(n+1)=2a(n)/(7-n)
675/225=3
225/90=5/2
90/45=2
45/30=3/2
30/30=1
30/()=1/2 =>()=60
675/225=3
225/90=5/2
90/45=2
45/30=3/2
30/30=1
30/()=1/2 =>()=60
a(n)/a(n+1)=3-(n-1)/2
a(n+1)=2a(n)/(7-n)