def sumPowerSeries(int n){
    BigInteger sum = 0
    BigInteger seriesVal = 0
    
    for (int index = 1; index < n+1; index++) {
        seriesVal = index
        sum = sum + seriesVal.pow(index)
        //println " " + index + " " + sum 
    }
    return sum
}

Find the last ten digits of the series, 1^(1) + 2^(2) + 3^(3) + ... + 1000^(1000)

Groovy