O15-C902 > restart: > f:=(t,u)->111-1130/u+3000/t/u; > u:=array(0..20);u[0]:=2;u[1]:=-4; u := array(0 .. 20, []) u[0] := 2 u[1] := -4 > for k from 2 to 20 do u[k]:=f(u[k-2],u[k-1]) od:map(evalf,u); array(0 .. 20, [ (0) = 2. (1) = -4. (2) = 18.50000000 (3) = 9.378378378 (4) = 7.801152738 (5) = 7.154414481 (6) = 6.806784737 (7) = 6.592632769 (8) = 6.449465934 (9) = 6.348452057 (10) = 6.274438598 (11) = 6.218695740 (12) = 6.175837305 (13) = 6.142359081 (14) = 6.115883067 (15) = 6.094739439 (16) = 6.077722305 (17) = 6.063940322 (18) = 6.052721761 (19) = 6.043552110 (20) = 6.036031881 ]) > solve(r^3-111*r^2+1130*r-3000); 5, 6, 100 > p:=n->a*5^n+b*6^n+c*100^n; > s:=solve({p(0)=2,p(1)=u[2]*p(0),p(2)=u[3]*p(1)},{a,b,c}); s := {c = 0, a = -25, b = 27} > subs(s,p(n)); n n -25 5 + 27 6 > uu:=subs(s,p(n-1)/p(n-2));limit(uu,n=infinity); (n - 1) (n - 1) -25 5 + 27 6 uu := -------------------------- (n - 2) (n - 2) -25 5 + 27 6 6 >