/sys$common/syshlp/helplib.hlb FORTRAN, Data, Constants, Hollerith  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  A Hollerith constant is a string of printable characters preceded
  by a character count and the letter H.  It is used only in numeric
  expressions and has the form:

    nHc1c2c3...cn

  n  Is an unsigned, nonzero integer constant stating the
     number of characters in the string (including tabs and spaces).

  c  Is a printable character.

  A Hollerith constant can be a string of 1 to 2000 characters and is
  stored as a byte string, one character per byte.

  Hollerith constants have no data type, but assume a numeric data
  type according to the context in which they are used.