求助一VB数列问题,数学高手与VB高手来!!!

来源:百度知道 编辑:UC知道 时间:2024/07/16 16:02:11
已知
a = a
b = 2 * a + 1
c = 2 * (a + b) + 1
d = 2 * (a + b + c) + 1
e = 2 * (a + b + c + d) + 1
......

求满足当n=a+b+c+......时a的值!
(n由用户输入)
答案满意的话追加至一百分
难点是不知道有几项相加,不然我也会做。
如果a=1,则各项如下
a=1,b=3,c=9,d=27,e=81......

或则,谁能给我一个式子代码也可以加分
即第n项
n=2*(a+b+c+d+e+...)+1

Option Explicit
Dim St As String
Dim N As Long, N1 As Long, A As Long, B As Long, C As Long
Dim Last As Boolean

Private Sub Form_Load()
Form1.AutoRedraw = True
St = InputBox("一个任意整数", "输入", 1903)
If St = "" Then Exit Sub
If Val(St) < 1 Then Exit Sub
N = Val(St)
N1 = N
Last = False
Do While N1 <> 1 And (N1 * 2 + 1) Mod 3 = 0
If N1 - (N1 * 2 + 1) / 3 <> 0 Then
N1 = N1 - (N1 * 2 + 1) / 3
End If
Print N1
Last = True
Loop
A = N1
Print N; "="; A;
B = A
Do While B <> N
C = 2 * B + 1
Print "+"; C;
B = B + C
Loop
Print
Print "当n="; N; "时,a="; A
End Sub

已经运行过
够费劲的,不知道是不是符合楼主要求.

在VB里编个