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WikiCards · Card list · Science cards · Lah number
Common card · Science
Lah number, a Common card
In mathematics, the Lah numbers are coefficients expressing rising factorials in terms of falling factorials and vice versa.
- Rarity
- Common
- Domain
- Science
- ATK
- 57
- DEF
- 34
- Power
- 91
- Wikipedia reads a year
- 4,900
Power 91 (ATK + DEF): stronger than 35 % of WikiCards cards.
Lah number quiz: 3 questions
Three questions on the Lah number card, the way WikiCards duels ask them. Pick an answer, the facts are just below.
Find the missing word
They were ______ by Ivo Lah in 1954.
Answer
discovered. They were discovered by Ivo Lah in 1954. From the Lah number article on Wikipedia.
Which of these cards hits hardest (highest ATK)?
Answer
Tim Cluess. Tim Cluess 61 · Lah number 57 · Acoustic foam 53 · Corn oil 47 ATK in WikiCards.
Which of these Wikipedia articles is read the most in a year?
Answer
Coincidence. Coincidence 30,000 · Acoustic foam 19,000 · Lah number 4,900 · Charles McLean Andrews 2,200 Wikipedia reads over a year.
In a duel, each round asks a question like these about the opposing card, with 15 seconds to answer.
The facts on the card
The card carries these facts from its Wikipedia article.
- They were discovered by Ivo Lah in 1954.
- Explicitly, the unsigned Lah numbers L are given by the formula involving the binomial coefficient L = n ! k ! for n ≥ k ≥ 1, and the signed Lah numbers L ′ are related to them by L ′ = n L.
- Signed Lah numbers are only of historical interest as it's how they were defined in Lah's seminal paper, but their sign pattern make them of little to no use in formulas of mathematical interest.
Why it is Common
Rarity in WikiCards follows a year of Wikipedia page views: the most read articles become Epic and Legendary cards. The Lah number article was read about 4,900 times in a year. ATK comes from the length of the article and DEF from its quality, so this card hits with 57 and blocks with 34: each hit it takes is cut by 14 %.
How to get Lah number
Open packs. Each pack holds five cards drawn from real Wikipedia articles, the rarest last, and the fifth card is always Rare or better. The odds are shown in the game. A free pack arrives every hour and two can wait, and the Coins you win in duels buy more packs.
More Science cards
Cards close in power
The cards just above and just below Lah number in the power ranking, all domains together.
- AffileCommon · Society · ATK 52 DEF 39
- Caves of Aggtelek Karst and Slovak KarstCommon · Nature · ATK 53 DEF 38
- Everything Must GoCommon · Arts · ATK 52 DEF 39
- Portland Brownstone QuarriesCommon · Nature · ATK 51 DEF 40
- 1960 United States Senate election in MaineCommon · Society · ATK 58 DEF 33
- Tim CluessCommon · Society · ATK 61 DEF 30
Card lists
- Wikipedia quizNew questions every day
- All cards from A to ZEvery card, by name
- Science cards
- Legendary cards
- Tier listS and A tiers by power (ATK + DEF)
Credits
Text : Wikipedia, Lah number (revision), CC BY-SA 4.0. Photo : Watchduck You can name the author as "T. Piesk", "Tilman Piesk" or "Watchduck"., CC0, Wikimedia Commons.
