code: def R_nl(n, l, nu, r):
      """
      Returns the radial wavefunction R_{nl} for a 3d isotropic harmonic
      oscillator.
  
      Parameters
      ==========
  
      n :
          The "nodal" quantum number.  Corresponds to the number of nodes in
          the wavefunction.  ``n >= 0``
      l :
          The quantum number for orbital angular momentum.
      nu :
          mass-scaled frequency: nu = m*omega/(2*hbar) where `m` is the mass
          and `omega` the frequency of the oscillator.
          (in atomic units ``nu == omega/2``)
      r :
          Radial coordinate.
  
      Examples
      ========
  
      >>> from sympy.physics.sho import R_nl
      >>> from sympy.abc import r, nu, l
      >>> R_nl(0, 0, 1, r)
      2*2**(3/4)*exp(-r**2)/pi**(1/4)
      >>> R_nl(1, 0, 1, r)
      4*2**(1/4)*sqrt(3)*(3/2 - 2*r**2)*exp(-r**2)/(3*pi**(1/4))
  
      l, nu and r may be symbolic:
  
      >>> R_nl(0, 0, nu, r)
      2*2**(3/4)*sqrt(nu**(3/2))*exp(-nu*r**2)/pi**(1/4)
      >>> R_nl(0, l, 1, r)
      r**l*sqrt(2**(l + 3/2)*2**(l + 2)/factorial2(2*l + 1))*exp(-r**2)/pi**(1/4)
  
      The normalization of the radial wavefunction is:
  
      >>> from sympy import Integral, oo
      >>> Integral(R_nl(0, 0, 1, r)**2*r**2, (r, 0, oo)).n()
      1.00000000000000
      >>> Integral(R_nl(1, 0, 1, r)**2*r**2, (r, 0, oo)).n()
      1.00000000000000
      >>> Integral(R_nl(1, 1, 1, r)**2*r**2, (r, 0, oo)).n()
      1.00000000000000
  
      """
      n, l, nu, r = map(S, [n, l, nu, r])
  
      # formula uses n >= 1 (instead of nodal n >= 0)
      n = n + 1
      C = sqrt(
          (
              (2 * nu) ** (l + Rational(3, 2))
              * 2 ** (n + l + 1)
              * factorial(n - 1)
          )
          / (sqrt(pi) * (factorial2(2 * n + 2 * l - 1)))
      )
      return (
          C
          * r ** (l)
          * exp(-nu * r**2)
          * assoc_laguerre(n - 1, l + S.Half, 2 * nu * r**2)
      )
  
imports: from sympy.core import S, pi, Rational
  from sympy.functions import assoc_laguerre, sqrt, exp, factorial, factorial2
label_desc: Use image node_id 1 for calling a global function with example usage: R_nl(n, l, nu, r) and returns: unknown