From Wikipedia, the free encyclopedia
Adecagonal numberis afigurate numberthat represents adecagon.Then-th decagonal number is given by the formula
The first few decagonal numbers are:
- 0,1,10,27,52,85,126,175,232, 297, 370, 451, 540, 637, 742, 855, 976, 1105, 1242, 1387, 1540, 1701, 1870, 2047, 2232, 2425, 2626, 2835, 3052, 3277, 3510, 3751,4000,4257, 4522, 4795, 5076, 5365, 5662, 5967, 6280, 6601, 6930, 7267, 7612, 7965, 8326 (sequenceA001107in theOEIS)
Then-th decagonal number can also be calculated by adding the square ofnto thrice the (n—1)-thpronic numberor, to put it algebraically, as
Properties
- Decagonal numbers consistently alternateparity.
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Possessing a specific set of other numbers |
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Expressible via specific sums |
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