题解 | 尼科彻斯定理

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

/*

sum = n * a1 + (n(n-1))
a1 = sum/n - (n-1)

// 等差数列的首项是 n的平方 - n + 1，项数是n

*/

func main() {
    scanner := bufio.NewScanner(os.Stdin)
    scanner.Scan()

    n := scanner.Text()
    num,_ := strconv.ParseInt(n,10, 64)

    a1 := (num * num * num)/num - (num - 1)

    res := make([]int64,0)

    for i := int64(0); i < num;i++{
        res = append(res, a1)
        a1 += 2
    }

    var resStr string
    for i,v :=range  res{
        if i > 0{
            resStr += "+"
        }
        resStr += strconv.FormatInt(v,10)
    }


   fmt.Println(resStr)
}

等差数列的首项是 n的平方 - n + 1，项数是n