11 lines
499 B
Markdown
11 lines
499 B
Markdown
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Triangle, pentagonal, and hexagonal numbers are generated by the following formulae:
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Name | Formula | Numbers
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------------|----------------------|-------------------------
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Triangle | `T_{n} = n(n+1)/2` | `1, 3, 6, 10, 15, ...`
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Pentagonal | `P_{n} = n(3n-1)/2` | `1, 5, 12, 22, 35, ...`
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Hexagonal | `H_{n} = n(2n-1)` | `1, 6, 15, 28, 45, ...`
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It can be verified that `T285 = P165 = H143 = 40755`.
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Find the next triangle number that is also pentagonal and hexagonal.
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