может помочь следующий подход?
y1=[0,0]
y2=[0,0]
x1=[0,1,2,3,4,5,6,7,8,9,10]
x2=[0,1,2,3,4,5,6,7,8,9,10]
for t in range (2,11):
tempY1 = y1[t-1] + y1[t-2] + y2[t-1]+ x1[t] + x2[t] + 1
tempY2 = y1[t-1] + y2[t-1] + y2[t-2] +x1[t] + x2[t] + 1
y1.append(tempY1)
y2.append(tempY2)