80 (numerus)
80, numeris Romanis LXXX, litterisque octoginta scriptus, est numerus naturalis post 79 et ante 81. Numerus ordinalis congruens octoge(n)simus, numerus distributivus octogeni, adverbium numerale octogies est. Eius divisores sunt 1, 2, 4, 5, 8, 10, 16, 20, 40, et 80 ipse.
In mathematica
[recensere | fontem recensere]80 est:
- Summa functions totientis Euleri(en) φ(x) per primos integros sedecim.
- Numerus semiperfectus(en).[1]
- Numerus ménage(en).[2]
- Numerus palindromicus(en) in basibus 3 (22223), 6 (2126), 9 (889), 15 (5515), 19 (4419), et 39 (2239).
- Repdigitus(en) in basibus 3, 9, 15, 19, et 39.
- Summa primorum quattuor parium gemellorum(en) ((3 + 5) + (5 + 7) + (11 + 13) + (17 + 19)).
- Principium Pareto(en), etiam regula 80–20 appellatum, dicit, pro multis eventibus, 80 fere centesimas effectuum ex 20 centesimis causarum exoriri.[3][4]
Omnis configuratio aenigmatis 15(en) quae solvi potest in minus quam 80 motibus unius columnae solvitur.[5]
In chemia
[recensere | fontem recensere]Notae
[recensere | fontem recensere]- ↑ Sloane's A005835: Pseudoperfect (or semiperfect) numbers. . The On-Line Encyclopedia of Integer Sequences (OEIS Foundation).
- ↑ Sloane's A000179: Ménage numbers. . The On-Line Encyclopedia of Integer Sequences (OEIS Foundation).
- ↑ Bunkley, Nick (3 Martii 2008). "Joseph Juran, 103, Pioneer in Quality Control, Dies". The New York Times.
- ↑ "What is 80/20 Rule, Pareto's Law, Pareto Principle".
- ↑ A. Brüngger, A. Marzetta, K. Fukuda, et J. Nievergelt, "The parallel search bench ZRAM and its applications," Annals of Operations Research 90 (1999): 45–63 (PDF).
Nexus externi
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