sample         chars  M    h_2    h_3    h_4
    ------------- ------ -- ------ ------ ------
    engl-wow       56147 29  3.299  2.724  2.542
    port-ate       30180 40  3.288  3.034  3.206
    span-qui       32570 32  3.079  2.683  2.638
    ital-mnz       61078 32  3.191  2.764  2.660
    fran-mic       37317 39  3.269  2.746  2.796
    latn-bel       56410 24  3.295  2.689  2.418
    latn-ben       47336 26  3.322  2.723  2.485
    latn-ock       49347 25  3.257  2.525  2.222
    latn-gen       71165 24  3.302  2.651  2.334
    latn-dai       59435 22  2.420  1.909  1.696
    latn-zan       71165 24  2.974  2.388  2.347
    viet-www       23833 51  2.873  2.589  2.862
    chin-tao       26737 31  2.063  1.821  1.923
    chin-acc       13281 49  2.638  2.706  3.039
    voyn-pha       13326 20  2.123  1.938  2.064
    voyn-hea       44630 23  2.105  1.898  1.979
    voyn-heb       20029 20  2.106  1.882  2.003
    voyn-bio       37732 21  1.799  1.589  1.647
    vmrc-bio-w10   26334 31  2.433  2.331  2.564
    vmrc-bio-w20   22562 41  2.795  2.821  3.182
    vmrc-hea-w10   33175 33  2.708  2.582  2.856
    vmrc-hea-w20   28644 43  3.051  3.078  3.506
    vmrc-heb-w10   14601 30  2.713  2.662  3.002
    vmrc-heb-w20   12613 40  3.103  3.231  3.659
    vmrc-bio-p10   24168 32  2.729  2.620  2.936
    vmrc-bio-p20   19171 42  3.357  3.368  3.809
    span-qub       48955 32  3.103  2.692  2.607
    span-quc       48156 34  3.117  2.708  2.649
    span-qud      451577 34  3.110  2.618  2.269