>>929 (続き)

したがって
 a[n] = (2/3) -(1/6)(-1/2)^n +(1/2)(1/2)^n,
 b[n] = (2/3) +(1/3)(-1/2)^n,
 c[n] = (2/3) -(1/6)(-1/2)^n -(1/2)(1/2)^n,


>>948
 a[n] = p(n) + q(n),
 b[n] = p(n) + r(n),
 c[n] = q(n) + r(n),
だから、
 p(0) = 1, q(0) = 0, r(0) = 0,
なので
 p(n) = {2 + (-1/2)^n + 3(1/2)^n}/6,
 q(n) = {1 - (-1/2)^n}/3,
 r(n) = {2 + (-1/2)^n - 3(1/2)^n}/6,