FUSC Sequence

Write a script to generate first 50 members of FUSC Sequence.

The sequence defined as below:
fusc(0) = 0
fusc(1) = 1
for n > 1:
when n is even: fusc(n) = fusc(n / 2),
when n is odd: fusc(n) = fusc((n-1)/2) + fusc((n+1)/2)

#!/usr/bin/env tclsh
#
# Write a script to generate first 50 members of FUSC Sequence.
# fusc(0) = 0
# fusc(1) = 1
# for n > 1:
# when n is even: fusc(n) = fusc(n / 2),
# when n is odd: fusc(n) = fusc((n-1)/2) + fusc((n+1)/2)
#
proc fusc {n} {
    if {$n == 0}  {
        return 0
    } elseif {$n == 1} {
        return 1
    } elseif {$n > 1} {
        set checkn [tcl::mathop::% $n 2]
        if {$checkn==0} {
            return [fusc [tcl::mathop::/ $n 2]]
        } else {
            set subn [tcl::mathop::- $n 1]
            set addn [tcl::mathop::+ $n 1]
            return [tcl::mathop::+ [fusc [tcl::mathop::/ $subn 2]] [fusc [tcl::mathop::/ $addn 2]]]
        }
    } else {
        return -code error "Invalid input"
    }
}

set results [list]
for {set i 0} {$i < 50} {incr i} {
    lappend results [fusc $i]
}
set r [join $results ", "]
puts $r