The prime factors of n.

*To*: mathgroup at smc.vnet.net*Subject*: [mg32673] The prime factors of n.*From*: "Robert G. Wilson v" <rgwv at kspaint.com>*Date*: Wed, 6 Feb 2002 03:41:24 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hello all, I wish to receive a list of prime factors of n not in the form returned by FactorInteger. Instead I want only the primes the number of times they appear. As an example I will use 72. FactorInteger[72] gives { {2,3}, {3,2} }. I wish the list would read { 2, 2, 2, 3, 3 }. Is the following the best that I can do? f[n_Integer] := Module[{a = FactorInteger[n], b = {}}, While[Length[a] > 0, Do[b = Append[b, a[[1, 1]]], {a[[1, 2]]}]; a = Drop[a, 1]]; b] . See http://www.research.att.com/cgi-bin/access.cgi/as/njas/sequences/eisA.cgi?Anum=037276 Sincerely yours, Robert G. "Bob" Wilson, V

**Follow-Ups**:**Re: The prime factors of n.***From:*Ken Levasseur <Kenneth_Levasseur@uml.edu>

**Re: The prime factors of n.***From:*Sseziwa Mukasa <mukasa@jeol.com>

**Re: The prime factors of n.***From:*Tomas Garza <tgarza01@prodigy.net.mx>