The .NUMBER LEVEL command allows you to specify the beginning
    number of a sequence of headers. Enter this command immediately
    before the first .HEADER LEVEL command that you want to affect.
    Subsequent .HEADER LEVEL commands will each be one higher than
    the preceding one according to its level (see .HEADER LEVEL).
    (See also .STYLE HEADERS and .DISPLAY LEVELS.)

    Format

      .NUMBER LEVEL  [[+/-]n1] [,[+/-]n2]...[,[+/-]n6]

    Abreviated format

      .NMLV  [[+/-]n1] [,[+/-]n2]...[,[+/-]n6]