In the reflection formula for the polygamma function $$ \psi^{(n)}(1-z) + (-1)^{n+1}\psi^{(n)}(z) % = (-1)^{n} \pi \frac{d^{n}}{d z^{n}} \cot (\pi z) $$ the right hand side is a polynomial $(-1)^{n}\pi^{n+1} P_{n+1}(\cot \pi z)$. With $x=\cot \pi z$, the first few polynomials are: $$ x\\ -x^2-1\\ 2 x^3 + 2 x\\ -6 x^4 - 8 x^2 - 2\\ 24 x^5 +40 x^3 + 16 x\\ -120 x^6-240 x^4-136 x^2-16\\ $$ For a numerical library function I have already computed and stored coefficients up to $n=12$. The Wikipedia article gives a recursion formula for (slightly different) $P_{n+1}$ in terms of $P_n$ and $P_n'$. Now my question: Is there a known recurrence formula for computing the values $P_n(x)$ of the form like those for orthogonal polynomials \begin{align} P_n(a) &= a(n,x) P_{n-1}(x) + b(n,x) P_{n-2}(x), \quad\text{or maybe}\\ P_n(a) &= a(n,x) P_{n-1}(x) + b(n,x) P_{n-2}(x)+ c(n,x) P_{n-3}(x) \end{align} with (relative) simple expressions $a, b, c$? I do not want to compute and cache the coefficients for higher degrees; and I am open to other or better numerical algorithms.
2026-03-25 15:56:40.1774454200
Recurrence relation for polygamma reflection polynomials
204 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in SPECIAL-FUNCTIONS
- Generalized Fresnel Integration: $\int_{0}^ {\infty } \sin(x^n) dx $ and $\int_{0}^ {\infty } \cos(x^n) dx $
- Is there any exponential function that can approximate $\frac{1}{x}$?
- What can be said about the series $\sum_{n=1}^{\infty} \left[ \frac{1}{n} - \frac{1}{\sqrt{ n^2 + x^2 }} \right]$
- Branch of Math That Links Indicator Function and Expressability in a Ring
- Generating function of the sequence $\binom{2n}{n}^3H_n$
- Deriving $\sin(\pi s)=\pi s\prod_{n=1}^\infty (1-\frac{s^2}{n^2})$ without Hadamard Factorization
- quotients of Dedekind eta at irrational points on the boundary
- Sources for specific identities of spherical Bessel functions and spherical harmonics
- Need better resources and explanation to the Weierstrass functions
- Dilogarithmic fashion: the case $(p,q)=(3,4)$ of $\int_{0}^{1}\frac{\text{Li}_p(x)\,\text{Li}_q(x)}{x^2}\,dx$
Related Questions in RECURRENCE-RELATIONS
- Recurrence Relation for Towers of Hanoi
- Solve recurrence equation: $a_{n}=(n-1)(a_{n-1}+a_{n-2})$
- General way to solve linear recursive questions
- Approximate x+1 without addition and logarithms
- Recurrence relation of the series
- first order inhomogeneous linear difference equation general solution
- Guess formula for sequence in FriCAS
- Solve the following recurrence relation: $a_{n}=10a_{n-2}$
- Find closed form for $a_n=2\frac{n-1}{n}a_{n-1}-2\frac{n-2}{n}a_{n-2}$ for all $n \ge 3$
- Young Tableaux generating function
Related Questions in POLYGAMMA
- Series Representation of Gamma Function
- The meaning and definition of $\psi^{(-2)}(x)$, and the convergence of some related series involving the Möbius function
- Relation between harmonic series $H(m)$ and polygamma function?
- Logarithmic Sum
- $\sum_{n=1}^{4000000} \frac{1}{n^3}$ very quick.
- On the series expansion of $\frac{\operatorname{Li}_3(-x)}{1+x}$ and its usage
- Is the polygamma function of order $2$ non-negative (or negative) for all $x >0$?
- Is it possible to simplify $\psi^{(2)}(\frac18)$ or $\psi^{(2)}(\frac pq)$?
- Polygamma expression for $\frac{\Gamma^{(k)}(z)}{\Gamma(z)}$?
- Alternative proof for $\zeta\left(2,\frac14\right)=\psi^{(1)}\left(\frac14\right)=\pi^2+8G$
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?