int f(int* pnBuffer, int nSize, int nIndex)
{
    int nSum = 0;
    for(int i = 0; i < nSize; i++)
    {
        if(i == nIndex)
        {
            nSum += pnBuffer[i];
            nSum += pnBuffer[nSize - i - 1];
            nIndex *= nIndex;
            if(nIndex>nSize)
            {
                break;
            }
        }
    }
return nSum;
}