bool countonly = false
integer count = 0

procedure ncs(sequence rest, integer ri=0, sequence taken={}, bool contig=false, bool gap=false)
    if ri>=length(rest) then
        if contig then
            if countonly then
                count += 1
            else
                ?taken
            end if
        end if
    else
        ri += 1
        ncs(rest,ri,taken&rest[ri],gap,gap)
        ncs(rest,ri,taken,contig,length(taken)!=0)
    end if
end procedure

ncs({1,2,3})
?"==="
ncs({1,2,3,4})
?"==="
countonly = true
atom t0 = time()
sequence s = {}
for i=1 to 20 do
    count = 0
    ncs(tagset(i))
    s = append(s,count)
end for
?time()-t0
?s