$ perl -le'
use List::Util qw/sum/;
use List::MoreUtils qw/natatime/;

my @arr = (0,0,1, 3,2,0, 1,1,1);
my $it = natatime 3, @arr;
my @output;              
while ( my @vals = $it->() ) {
    push @output, sum @vals;
    }

print "@output";
'
1 5 3