Ch8.ipynb

Kernel: SageMath 10.3

def s(n):
    return n^2-7*n+3

['n','s(n)','s(n)-s(n-1)','s(n)-2s(n-1)']+list(map(lambda k: [k,s(k),s(k)-s(k-1),s(k)-2*s(k-1)+s(k-2)],range(2,5)))

['n',
 's(n)',
 's(n)-s(n-1)',
 's(n)-2s(n-1)',
 [2, -7, -4, 2],
 [3, -9, -2, 2],
 [4, -9, 0, 2]]