>>843

S = 1 + Σ(k=1,∞) a[n] = 3.91202535564143

(1)
 a[n] 〜 11.12728469988 / S^n → 0 (n→∞)

(2)
 b[n+1] ≒ n・b[n]/{b[1]+b[2]+…+b[n]} → 1,