Tens Combos - Ruby

$results = { :ignore => [], :include => [], 1 => [], 2 => [], 4 => [], 8 => [] }

def sum_array (numbers)
    n = 0
    for i in 0...numbers.length
        n += numbers[i]
    end
    return n
end

def dec_to_array (n)
    array = []
    numbers = [1,2,1,3,6].reverse()
    for i in 0..4
        a = 2.pow(i)
        if (n & a == a)
            array.push(numbers[i])
        end
    end
    return array
end

# Calculate included and excluded values
for i in 0...32
    array = dec_to_array(i)
    sum = sum_array(array)
    if (sum > 9 || i >> 3 == 3)
        $results[:ignore].push(i)
    else
        $results[:include].push(i)

        # Fill out bit-results
        for j in 0..3
            a = 2.pow(j)
            if (sum & a == a)
                $results[a].push(i)
            end
        end
    end
end

File.open("./tens_combos.txt", 'w') { |file|
    file.puts "32 total combinations"
    for i in 0...$results.keys.length
        result = $results[$results.keys[i]]
        file.puts "------------|| #{$results.keys[i]} (#{result.length} combos) ||------------"
        for j in 0...result.length
            dec = result[j]
            file.puts "#{dec_to_array(dec).to_s} = #{dec}"
        end
    end
    file.puts "\n"
    for i in 0...$results.keys.length
        result = $results[$results.keys[i]]
        file.puts "------------|| #{$results.keys[i]} (#{result.length} combos) ||------------"
        for j in 0...result.length
            file.print "#{result[j]}"
            if (j < result.length - 1)
                file.print(",")
            end
        end
        file.print("\n")
    end
}

# MAPPING RESULTS

# 1-bit
# F = 11'3' + 1'13' + 1'1'3 + 113

# 2-bit
# F = 1'2'1'36' + 1'2'3'6 + 113'6' + 23'6' + 11'6 + 213

# 4-bit
# F = 1'2'3'6 + 11'6 + 13 + 23 + 13(second 1)

# 8-bit
# F = 116 + 26 + 36