How to calculate this equation?
The sagemath with symbolic computations doesn't provide the same results. Contact the authors.
n = var('n');
a = 0.442
b = 0.0001
c = 0.0018
d = 0.0138
(2*n+2)*a + (2*n)*b + (2*n+2)*c + (2*n)*d

output
0.915400000000000*n + 0.887600000000000

$$(2*n+2)*a + (2*n)*b + (2*n+2)*c + (2*n)*d = $$
$$ 2n(a+b+c+d) + 2(a +c) $$
$$ 2n ( 0.442 + 0.0001 + 0.0018 + 0.0138) + 2 (0.442 + 0.0018)$$
$$ 2n ( 0.442 + 0.0019 + 0.0138) + 2 (0.4439)$$
$$ 2n ( 0.4439 + 0.0138) + 0.8878)$$
$$ 2n ( 0.4577 ) + 0.8878)$$
$$  0.9154n  + 0.8878)$$