43 (number)

Forty-three is the 14th smallest prime number. The previous is forty-one, with which it comprises a twin prime, and the next is 47. 43 is the smallest prime that is not a Chen prime. It is also the third Wagstaff prime.[1]

43 is the fourth term of Sylvester's sequence, one more than the product of the previous terms (2 × 3 × 7).[2]

43 is a centered heptagonal number.[3]

Let a₀ = a₁ = 1, and thenceforth a_n = 1/n − 1(a₀² + a₁² + ... + a_{n − 1}²). This sequence continues 1, 1, 2, 3, 5, 10, 28, 154... (sequence A003504 in the OEIS). a₄₃ is the first term of this sequence that is not an integer.

43 is a Heegner number.[4]

43 is the largest prime which divides the order of the Janko group J₄.

43 is a repdigit in base 6 (111).

43 is the number of triangles inside the Sri Yantra.

43 is the largest natural number that is not an (original) McNugget number.[5]

43 is the smallest prime number expressible as the sum of 2, 3, 4, or 5 different primes:

• 43 = 41 + 2
• 43 = 11 + 13 + 19
• 43 = 2 + 11 + 13 + 17
• 43 = 3 + 5 + 7 + 11 + 17.

43 is the smallest number with the property 43 = 4*prime(4) + 3*prime(3). Where prime(n) is the n-th prime number. There are only two numbers with that property, the other one is 127.

When taking the first six terms of the Taylor series for computing e, one obtains

${\displaystyle \sum _{i=0}^{5}{\frac {1}{i!}}={\frac {163}{60}}=2+{\frac {43}{60}},\ }$

which is also five minus the fifth harmonic number.

Every solvable configuration of the Fifteen puzzle can be solved in no more than 43 multi-tile moves (i.e. when moving two or three tiles at once is counted as one move).[6]

• The chemical element with the atomic number 43 is technetium. It has the lowest atomic number of any element that does not possess stable isotopes.

In auto racing:

• The number for Richard Petty's race car when he won his seven Winston Cup Championships. He also won 200 races in his career, 95% of them in the famous #43.
• The maximum number of cars participating in a NASCAR race in the Cup Series until 2016, and, through the 2012 season, the Nationwide Series.

In American football:

• Strong safety Troy Polamalu wore #43 for the Pittsburgh Steelers and played his entire NFL career with the team for eleven seasons (2003–2014).

Forty-three is:

• +43, the code for direct dial international phone calls to Austria.
• Bush 43, George W. Bush, 43rd President of the United States.[7]
• "43", a song by Level 42 on the album Level 42.
• "43", a song by metal band Mushroomhead on the albums Mushroomhead and XX.
• USS Coral Sea (CV-43) (aircraft carrier).
• The name of a popular Spanish liqueur, Cuarenta y tres, which is distilled with 43 different herbs and spices.

• List of highways numbered 43

• Lehmer, Derrick, List of prime numbers from 1 to 10,006,721, Carnegie Institution of Washington, 1914
• Wells, David, Prime Numbers: The Most Mysterious Figures in Math, Wiley, 2005, ISBN 0-471-46234-9
• Crandall, Richard and Pomerance, Carl, Prime Numbers: A Computational Perspective, Springer, 2005, ISBN 0-387-25282-7
• http://www.espncricinfo.com/south-africa-v-sri-lanka-2011/content/current/story/548918.html