程序代码：

#include <stdio.h>

int count = 0;

int judge(int a[], int len, int key)
{
    int i;
    if (len && a[0] == key)    return 1;
    for (i = 1;i < len;++i)
    {
        if (a[i] == key)    return 1;
    }
    switch(key)
    {
    case 1:case 3:case 7:
    case 9:return 0;
    default:break;
    }
    for (i = 0;i < len;++i)
    if (key * 2 == a[i] + a[i-1])
        return 1;
    return 0;
}

void Output(int a[], int len)
{
    count++;
    for (int i = 0;i < len-1;++i)
        printf("%d ", a[i]);
    printf("%d\n", a[i]);
}

void fun(int a[], int ip, int all)
{
    if (ip == all)
    {Output(a, all);return;}
    for (int i = 1;i < 10;++i)
    {
        if (judge(a, ip, i))    continue;
        a[ip] = i;
        fun(a, ip+1, all);
    }
}

int main()
{
    int i, a[10] = {0};
    freopen("out.txt", "w", stdout);
    for (i = 4;i < 10;++i)
        fun(a, 0, i);
    printf("%d\n", count);
    fclose(stdout);
    return 0;
}