>>86

漸化式から、n>>1 では
　a[n] 〜 α{1 -1/(4n) -3/(32n^2) -1/(384n^3) +361/(6144n^4) +12799/(122880n^5) +(377221/2449120n^6) + …}
　　　 〜 α(1 - 1/n)^(1/4),

　ここに　α = lim(n→∞) a[n],

[前スレ.609] では
　a[1] = 0,　a[2] = 1/3,　a[3] = 1/3,　a[4] = 12/35,　a[5] = 47/135,
　a[6] = 731/2079,　a[7] = 1772/5005, a[8] = 20609/57915,
　a[9] = 1119109/3132675,　a[10] = 511144/1426425,　…,　a[∞] = 1/e