| 释义 | Golomb-Dickman ConstantN.B. A detailed on-line essay by S. Finchwas the starting point for this entry. 
 Let  be a Permutation of  elements, and let  be the number of Cycles of length  in this Permutation.  Picking  at Random gives 
 |  | (1) | 
 |  | (2) | 
 (Shepp and Lloyd 1966, Wilf 1990).  Goncharov (1942) showed that|  | (3) | 
 which is a Poisson Distribution, and|  | (4) | 
 which is a Normal Distribution,|  | (5) | 
 is the Euler-Mascheroni Constant, and  is the Normal Distribution Function.  Let 
 Golomb (1959) derived
 
 which is known as the Golomb Constant or Golomb-Dickman constant. Knuth (1981) asked for the constants|  | (8) | 
 and  such that 
 and Gourdon (1996) showed that|  | (9) | 
 where|  | (10) | 
 |  | (11) | 
 can be expressed in terms of the function  defined by  for  and 
 for|  | (12) | 
 , by 
 Shepp and Lloyd (1966) derived|  | (13) | 
 Mitchell (1968) computed
  to 53 decimal places. 
 Surprisingly enough, there is a connection between  and Prime Factorization (Knuth and Pardo 1976, Knuth 1981, pp. 367-368, 395, and 611).  Dickman (1930) investigated the probability  that the largest Prime Factor  of a random Integer between 1 and  satisfies  for  .  He found that 
 Dickman then found the average value of|  | (15) | 
 such that  , obtaining 
 which is
  . References
 Finch, S.  ``Favorite Mathematical Constants.''  http://www.mathsoft.com/asolve/constant/golomb/golomb.htmlGourdon, X.  1996.  http://www.mathsoft.com/asolve/constant/golomb/gourdon.html. Knuth, D. E.  The Art of Computer Programming, Vol. 1: Fundamental Algorithms, 2nd ed.  Reading, MA: Addison-Wesley, 1973. Knuth, D. E.  The Art of Computer Programming, Vol. 2: Seminumerical Algorithms, 2nd ed.  Reading, MA: Addison-Wesley, 1981. Knuth, D. E. and Pardo, L. T.  ``Analysis of a Simple Factorization Algorithm.''  Theor. Comput. Sci. 3, 321-348, 1976. Mitchell, W. C.  ``An Evaluation of Golomb's Constant.''  Math. Comput. 22, 411-415, 1968. Purdom, P. W. and Williams, J. H.  ``Cycle Length in a Random Function.''  Trans. Amer. Math. Soc. 133, 547-551, 1968. Shepp, L. A. and Lloyd, S. P.  ``Ordered Cycle Lengths in Random Permutation.''  Trans. Amer. Math. Soc. 121, 350-557, 1966. Wilf, H. S.  Generatingfunctionology, 2nd ed.  New York: Academic Press, 1993. |