Single character search results on google

Here are the top results on google for the characters {A-Z,0-9}

a - http://www.apple.com/
b - http://www.bhphotvideo.com
c - http://www.c-span.org/
d - http://www.dlink.com/
e - http://www.eonline.com/
f - http://www.fuckedcompany.com/
g - http://gmail.google.com/
h - http://www.h-net.org/
i - http://www.apple.com/itunes/
j - http://www.jenniferlopez.com/
k - http://www.kmart.com/
l - http://www.iht.com/
m - http://www.mibank.com/
n - http://www.kn.pacbell.com/wired/bluewebn/
o - http://www.oreilly.com/
p - http://www.sloan.org/
q - http://www.q4music.com/
r - http://www.r-project.org/
s - http://www.mcdonalds.com/
t - http://www02.sbc.com/ (at&t)
u - http://www.arizona.edu/
v - http://vforvendetta.warnerbros.com/
w - http://www.starwoodhotels.com/whotels/
x - http://www.x.org/
y - http://messenger.yahoo.com/
z - http://www.atozteacherstuff.com/

0 - http://www.business2.com/
1 - http://www.vh1.com/
2 - http://www.internet2.edu/
3 - http://www.3com.com/
4 - http://www.channel4.com/
5 - http://www.adobe.com/shockwave/download/index.cgi….
6 - http://www.apple.com/quicktime/download/
7 - http://au.yahoo.com/
8 - http://www.super8.com/
9 - http://www.michaelmoore.com/

Results for letters L, P & T did not have the letters in thier URL, but they were quite prominent in the page titles. When it comes to numbers, - 5, 6, 7 & 9 were not present in the URL!.

Wondering what algorithm is used to rank these pages!