147 (one hundred [and] forty-seven) is the natural number following 146 and preceding 148.
In mathematics
147 is the fourth centered icosahedral number. These are a class of figurate numbers that represent points in the shape of a regular icosahedron or alternatively points in the shape of a cuboctahedron, and are magic numbers for the face-centered cubic lattice. Separately, it is also a magic number for the diamond cubic.
It is also the fourth Apéry number <math>a_3</math> following 19, where <math display=block>a_n=\sum_{k=0}^n\binom{n}{k}^2\binom{n+k}{k},</math>
with 147 the composite index of the nineteenth triangle number, 190.
There are 147 different ways of representing one as a sum of unit fractions with five terms, allowing repeated fractions, and 147 different self-avoiding polygonal chains of length six using horizontal and vertical segments of the integer lattice.
See also
- 147 (disambiguation)
References
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