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Everything about Pentagonal number

Figurate number

A pentagonal number is a figurate number that extends the concept of triangular and square numbers to the pentagon, but, unlike the first two, the construction of pentagonal numbers creates a pattern of inside dots that are not rotationally symmetrical. The nth pentagonal number pn is the number of distinct dots in a pattern of dots consisting of the outlines of regular pentagons with sides up to n dots, when the pentagons are overlaid so that they share one vertex. For instance, the third one is formed from outlines comprising 1, 5 and 10 dots, but the 1, and 3 of the 5, coincide with 3 of the 10 – leaving 12 distinct dots, 10 in the form of a pentagon, and 2 inside. Wikipedia →

🧭 Start here: a 6-step reading path

  1. Read the overview: Pentagonal numberA 5-minute orientation
  2. Skim a recent paper: Study on multi-objective linear fractional programming problem involving pentagonal intuitionistic fuzzy numberInfluential work since 2022
  3. Pick up a classic book: Amulets and superstitionsThe most-reprinted book on the subject
  4. Read the landmark paper: The truncated pentagonal number theoremCited 106 times
  5. Go sideways: Pell numberA closely related topic
  6. Go sideways: Triangular numberA closely related topic

📖 Definitions

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🏆 Landmark papers (most cited)

🆕 Influential since 2022

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