1. Pentagonal numberA pentagonal number is a figurate number that extends the concept of triangular and square numbers to the pentagon, but, unlike the first two, the patterns involved in the construction of pentagonal numbers 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 whose sides contain 1 to n dots, overlaid so that they share one vertex.
Read “Pentagonal number” on English Wikipedia
Read “五角数” on Japanese Wikipedia
Read “Pentagonal number” on DBpedia
Read “Pentagonal number” on English Wikipedia
Read “五角数” on Japanese Wikipedia
Read “Pentagonal number” on DBpedia
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