43 number: Encyclopedia - 43 number

43 (number)

43 is the natural number following 42 and preceding 44.

<< 40 41 42 43 44 45 46 47 48 49 >>

List of numbers -- Integers

0 10 20 30 40 50 60 70 80 90 >>

43 number - In mathematics

Forty-three is the 14th smallest prime number. The previous is forty-one, with which it comprises a twin prime, the next is forty-seven. 43 is a centered heptagonal number. 43 is the smallest prime that is not a Chen prime.

Let a(0) = a(1) = 1, and thenceforth a(n) = (a(0)² + a(1)² + ... + a(n-1)²) / (n-1). This sequence continues 1 1 2 3 5 10 28 154... (sequence A003504 in OEIS). Amazingly, a(43) is the first term of this sequence that is not an integer.

Negative forty-three (-43) is a Heegner number.

43 number - In science

43 number - In the periodic table

• The chemical element with the atomic number 43 (technetium) is the element with the lowest ordinal number, which does not possess stable isotopes. The technetium preceding element 42 (molybdenum) and the technetium following element 44 (ruthenium) have stable isotopes.

43 number - In astronomy

43 number - In other fields

Forty-three is also:

• The designation of Interstate 43, a freeway in Wisconsin.
• The code for direct dial international phone calls to Austria.
• Part of the title of the historical British comedy show Hancock's Forty-Three Minutes, starring Tony Hancock.
• The number of poppadoms ordered by the nine guests at a curry restaurant in Rowan Atkinson's classic Indian Waiter stand-up comedy sketch.
• Part of the title of a historical short story by Hershel Finman titled Forty-Three Rubles, about Rabbi Zvi Elimelech Spira.
• The year AD 43, 43 BC, and 1943.

Adapted from the Wikipedia article "43 number", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki