Log of N-factorial
     N           Actual          FACTLN(N)
     1          0.000000          0.000000
     2          0.693147          0.693147
     3          1.791759          1.791759
     4          3.178054          3.178054
     5          4.787492          4.787492
     6          6.579251          6.579251
     7          8.525162          8.525162
     8         10.604603         10.604603
     9         12.801827         12.801827
    10         15.104413         15.104413
    11         17.502308         17.502308
    12         19.987215         19.987215
    13         22.552164         22.552164
    14         25.191221         25.191221
    15         27.899273         27.899271
    20         42.335617         42.335617
    25         58.003605         58.003605
    30         74.658234         74.658234