727
  I’m sure green_bladder would have posted the Boeing 727.
  This plane had its own stairway built into the tail section. Hijacker DB Cooper utilized this feature to parachute out of a 727 somewhere over the American Southwest on Nov 24, 1971 with $200,000 ransom.
  The plane is also seen in the movie “Contact” as the private jet of billionaire SR Haddon (John Hurt). Jodie Foster boards the plane from the built-in stairway.
          728
  these are 3 of the 4 digits of my website www.1728.com
Needless to say it is heavily number-oriented with lots of calculators.
          729
  726 = 9[sup]3[/sup] or 3[sup]6[/sup]
oops typo
    729 = 9[sup]3[/sup] or 3[sup]6[/sup]
730 - an ungodly time to wake up in the morning
Japan’s infamous Unit 731.
Shit, I was on the wrong page there. I guess wolf_meister was correct 
Kül, brother of Bilge Khan and co-administrator of the Gokturk empire was born in 732 AD.
A high-rise residential building is located at 733 Park Avenue in the Lenox Hill neighborhood of Manhattan Island.
Morning Star Lodge 734 in Canton, IL.
Memorial Performing Arts Theater has 735 seats.
          736
  factors neatly into 23 * 32
  nice pallindromic pairing there.
A small correction on the 727 posting. DB Cooper parachuted over the American Northwest.
Never post when you are tired.
I’ll leave 737 for green_bladder.
738 = 123 x 6
1 x 2 x 3 = 6
          739
  = 7[sup]3[/sup] + 6[sup]3[/sup] + 5[sup]3[/sup] + 4[sup]3[/sup] - 3[sup]2[/sup]
          740
  = 4[sup]2[/sup] + 18[sup]2[/sup] + 20[sup]2[/sup]
          741
  741 is the 38th triangular number, being the sum of the integers 1 through 38.
742 Evergreen Terrace - a good place to live in the event of a nuclear blast, as the many layers of lead paint provide protection from the radiation.
743 A quick way of saying Boeing 747-300
Auf Meinen Lieben Gott, BWV 744 - Chorale prelude for organ by Johann Sebastian Bach.