183 (number)

Template:Infobox number 183 (one hundred [and] eighty-three) is the natural number following 182 and preceding 184.

In mathematics

183 is a perfect totient number, a number that is equal to the sum of its iterated totients.

Because $183=13^2+13+1$, it is the number of points in a projective plane over the finite field ${\mathbb{Z}}_{13}$. It is a repdigit in tredecimal (111₁₃). 183 is the fourth element of a divisibility sequence $1,3,13,183,\dots$ in which the $n$th number $a_n$ can be computed as $$a_n=a_{n-1}^2+a_{n-1}+1=\lfloor x^{2^n}\rfloor ,$$ for a transcendental number $x\approx 1.38509$. This sequence counts the number of trees of height $\le n$ in which each node can have at most two children.

There are 183 different semiorders on four labeled elements.

See also

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References

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