+∘÷\ 16⍴1
1 2 1.5 1.66667 1.6 1.625 1.61538 1.61905 1.61765 
      1.61818 1.61798 1.61806 1.61803 1.61804 
      1.61803 1.61803

   (1+5*0.5)÷2
1.61803
   20 ⍕ (1+5*0.5)÷2
 1.618033988749895_____

   1 ∧ +∘÷\ 16⍴1
1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597

In J:

   (+%) /\ 16 $ 1r1
1 2 3r2 5r3 8r5 13r8 21r13 34r21 55r34 89r55 144r89 233r144 
      377r233 610r377 987r610 1597r987