#J (10)

Very, very, very inspired by the answer of @Dennis:

<.@%~^&1.5

And a slightly longer, but with better performance (I suspect):

<.@(-:&.^.)

floor(halve under log)

To execute, indented parts are input:

   f=:<.@%~^&1.5
   f 0 8 12 16
0 2 3 4
   g=:<.@(-:&.^.)
   g 0 8 12 16
0 2 3 4

J (10)

Very, very, very inspired by the answer of @Dennis:

<.@%~^&1.5

And a slightly longer, but with better performance (I suspect):

<.@(-:&.^.)

floor(halve under log)

To execute, indented parts are input:

   f=:<.@%~^&1.5
   f 0 8 12 16
0 2 3 4
   g=:<.@(-:&.^.)
   g 0 8 12 16
0 2 3 4

#J (10)

Very, very, very inspired by the answer of @Dennis:

<.@%~^&1.5

And a slightly longer, but with better performance (I suspect):

<.@(-:&.^.)

floor(halve under log)

To execute, indented parts are input:

   f=:<.@%~^&1.5
   f 0 8 12 16
0 2 3 4
   g=:<.@(-:&.^.)
   g 0 8 12 16
0 2 3 4

#J (10)

Very, very, very inspired by the answer of @Dennis:

<.@%~^&1.5

And a slightly longer, but with better performance (I suspect):

<.@(-:&.^.)

floor(halve under log)

To execute, indented parts are input:

   f=:<.@%~^&1.5
   f 0 8 12 16
0 2 3 4
   g=:<.@(-:&.^.)
   g 0 8 12 16
0 2 3 4

J (10)

Very, very, very inspired by the answer of @Dennis:

<.@%~^&1.5

And a slightly longer, but with better performance (I suspect):

<.@(-:&.^.)

floor(halve under log)

To execute, indented parts are input:

   f=:<.@%~^&1.5
   f 0 8 12 16
0 2 3 4
   g=:<.@(-:&.^.)
   g 0 8 12 16
0 2 3 4

#J (10)

Very, very, very inspired by the answer of @Dennis:

<.@%~^&1.5

And a slightly longer, but with better performance (I suspect):

<.@(-:&.^.)

floor(halve under log)

To execute, indented parts are input:

   f=:<.@%~^&1.5
   f 0 8 12 16
0 2 3 4
   g=:<.@(-:&.^.)
   g 0 8 12 16
0 2 3 4