43 (number)

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

Cardinal 43
forty-three
Ordinal 43rd
forty-third
Factorization prime
Divisors 1, 43
Roman numeral XLIII
Binary 101011
Hexadecimal 2B

Contents

[edit] 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 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 7
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.

[edit] In science

[edit] Astronomy

[edit] 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.

Mad Magazine created the game 43-Man Squamish.

  • The number of consecutive district titles trying to be won by St. Francis de Sales of Toledo Ohio (a national record in any high school sport).

Pittsburgh Steelers DB Troy Polumalu wears 43

  • Skateboarders in San Francisco noticed that the number 43 appears everywhere for them in the early 80's. On receipts, credit card numbers, hotel rooms, bar codes, phone numbers, newspaper articles, events, the time of day, license plates or anything that had some kind of number on it. The number spread through to the rest of California and the East Coast. (Reference: Issue #43: The Skateboard Mag)

Houston Astros Pitcher Chris Sampson wears 43

[edit] In other fields

Forty-three is:

[edit] Historical years

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