Need Help solving second order differential equations

[SkewedZone]

So I have been working on a code to solve a coupled system of second order differential equations, in order to obtain the numerical solution of an elastic-pendulum. I've written the code needed to get the results and plot them, but I keep getting the following error: "TypeError: <lambda>() missing 1 required positional argument: 'd'". I really appreciate any help. Here's the code:

import numpy as np
import matplotlib.pyplot as plt
from scipy.integrate import odeint
import math

ci = [0.01, 0., 0., 0.0156613949, 0.00237, 0.]


def solver(t, pinit):
    return odeint(lambda a,b,d : [a[1], -4*math.pi*math.pi*a[0]*(math.sqrt(a[0]*a[0]+b[0]*b[0]+d[0]*d[0])- 3/4)/math.sqrt(a[0]*a[0]+b[0]*b[0]+d[0]*d[0]),b[1], -4*math.pi*math.pi*b[0]*((a[0]**(2)+b[0]**(2)+d[0]**(2))**(1/2) - 3/4)/(a[0]**(2)+b[0]**(2)+d[0]**(2))**(1/2), d[1],-4*math.pi*math.pi*d[0]*(math.sqrt(a[0]**(2)+b[0]**(2)+d[0]**(2)) - 3/4)/math.sqrt(a[0]**(2)+b[0]**(2)+d[0]**(2)) - math.pi*math.pi], pinit, t)


time = np.arange(0, 500.0, 0.01)
solution = solver(time, ci)
plt.plot(solution[:,0], solution[:,2])
plt.show()