>>736
a[1]=a(1+x)
a[n+1]=(1+x)(a[n]+a)

a[n+1]+{a(1+x)/x}=(1+x)[a[n]+{a(1+x)/x}]

a[n]+{a(1+x)/x}=[a[1]+{a(1+x)/x}]*{(1+x)^(n-1)}

a[n]=[a[1]+{a(1+x)/x}]*{(1+x)^(n-1)}-{a(1+x)/x}
=[a(1+x)+{a(1+x)/x}]*{(1+x)^(n-1)}-{a(1+x)/x}
=[a{(1+x)^2}/x]*{(1+x)^(n-1)}-{a(1+x)/x}
={a(1+x)/x}*[{(1+x)^n}-1]