{x^\:-1_ x}1+!:5
(1 1 1 1.0
 2 4 8 16.0
 3 9 27 81.0
 4 16 64 256.0
 5 25 125 625.0)

  +{x^\:-1_ x}1+!:5
(1 2 3 4 5.0
 1 4 9 16 25.0
 1 8 27 64 125.0
 1 16 81 256 625.0)