43 (number)

← 42 43 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 →
Cardinal	forty-three
Ordinal	rd
Factorization	prime
Divisors	1, 43
Greek numeral	ΜΓ´
Roman numeral	XLIII
Binary	1010112
Ternary	11213
Senary	1116
Octal	538
Duodecimal	3712
Hexadecimal	2B16

43 (forty-three) is the natural number following 42 and preceding 44.

In mathematics

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

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

43 is a centered heptagonal number.

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 the OEIS). Amazingly, a(43) is the first term of this sequence that is not an integer.

43 is a Heegner number.

43 is a repdigit in base 6 (111).

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

This is the smallest number, which draws up as sum of 2,3,4,5 different primes: 43=41+2 43=11+13+19 43=2+11+13+17 43=3+5+7+11+17. The following date magic square illustrates the magic constant as the sum of four primes:

4	15	17	07
5	19	13	6
20	9	2	12
14	0	11	18

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

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

which is also five minus the fifth harmonic number.

43 is also 42 + 1, 4+3 = 7, 40 +3, 6x7 + 1, 13+ 3x10, 7^2 -6, 3x7+13=34 + 3^2, 13x3 +6, and 3^3 + 2^4. These attributes are perhaps coincidental.

In science

• 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.

Astronomy

• Messier object M43, a magnitude 7.0 H II region in the constellation of Orion, a part of the Orion Nebula, and also sometimes known as de Mairan's Nebula

• The New General Catalogue object NGC 43, a barred spiral galaxy in the constellation Andromeda

• The Saros number of the solar eclipse series which began on April 29, 1513 BC and ended on June 5, 233 BC . The duration of Saros series 43 was 1280.1 years, and it contained 72 solar eclipses.

• The Saros number of the lunar eclipse series which began on August 27, 1482 BC and ended on March 15, 70. The duration of Saros series 43 was 1550.5 years, and it contained 87 lunar eclipses.

In sports

In professional sports in the United States, the jersey number 43 has been retired for Jim Norton of Tennessee (NFL) and Dennis Eckersley of the Oakland Athletics.

In NASCAR:

• The number for Richard Petty's race car when he won his 7 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 collegiate sports, the jersey number 43 is currently worn by forward Danny Gergen of the Johns Hopkins University Men's Basketball team. Gergen, a 6'5 sophomore from Austin, Texas, is averaging 23.8 minutes, 7.6 points, 1.8 rebounds, 2.0 assists and 0.8 steals in five games for the Blue Jays this season after being limited to only 35 minutes of playing time as a freshman. Gergen is also well-known for a dwarf-hating tantrum he went on in his freshman year. He later apologized for his hateful words.

In other fields

Forty-three is:

• The designation of Interstate 43, a freeway in Wisconsin.
• The code for direct dial international phone calls to Austria.
• "43", a song by Level 42 on the album Level 42
• "43," a song by Mushroomhead on the album "Mushroomhead"
• George W. Bush, 43rd president of the United States
• U.S.S. 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

Historical years

43 A.D., 43 B.C., 1943, 2043, etc.

References

• 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 0471462349
• Crandall, Richard and Pomerance, Carl, Prime Numbers: A Computational Perspective, Springer, 2005, ISBN 0387252827