19/04/18 14:48:47.34 HAU6+oOO.net
>>100 >>133
2次式で
f(x) = n! {1 + n(x-n) + b_n (x-n)(x-n-1)}, (n<x<n+1)
はどうでせう？
(1/n)b_{n-1} + b_n = n -1 +1/n,
これを解くと
b_n = n -2 +(4/n!)Σ[k=0,n-1] (-1)^(n-1-k)･k!
b_1 = 3, b_2 = 0, b_3 = 7/3, b_4 = 8/3, b_5 = 11/3, ････