local tab = {
    {0,3,1,7,5,9,8,6,4,2}, {7,0,9,2,1,5,4,8,6,3},
    {4,2,0,6,8,7,1,3,5,9}, {1,7,5,0,9,8,3,4,2,6},
    {6,1,2,3,0,4,5,9,7,8}, {3,6,7,4,2,0,9,5,8,1},
    {5,8,6,9,7,2,0,1,3,4}, {8,9,4,5,3,6,2,0,1,7},
    {9,4,3,8,6,1,7,2,0,5}, {2,5,8,1,4,3,6,7,9,0}
}
function check( n )
    local idx, a = 0, tonumber( n:sub( 1, 1 ) )
    for i = 1, #n do
        a = tonumber( n:sub( i, i ) )
        if a == nil then return false end
        idx = tab[idx + 1][a + 1]
    end
    return idx == 0
end
local n, r
while( true ) do
    io.write( "Enter the number to check: " )
    n = io.read(); if n == "0" then break end
    r = check( n ); io.write( n, " is " )
    if not r then io.write( "in" ) end
    io.write( "valid!\n" )
end