sun=2+5+8+11..输入整数n 求sum的前n项之和

是用什么语言,用C语言可以吗?
原程序:

main()
{
int sum=0,i,n,l=2;
scanf("%d",&n);
for(i=1;i<=n;i++)
{
sum=sum+l;
l=l+3;
}
printf("%d",sum);
}

vb

Private Sub Command1_Click()
n = Val(InputBox("请输入n"))
Dim sum As Integer
sum = 0
For i = 1 To n
sum = sum + i * 3 - 1

Next
MsgBox sum
End Sub

Pascal语言
这样就大结集了

var i,sum,m,n:longint;
begin
sum:=2;
m:=5;
readln(n);
for i:=1 to n-1 do
begin
inc(sum,m);
inc(m,3);
end;
writeln(sum);
end.