package main

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

var iost *Iost

type Iost struct {
	Scanner *bufio.Scanner
	Writer  *bufio.Writer
}

func NewIost(fp io.Reader, wfp io.Writer) *Iost {
	const BufSize = 2000005
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, BufSize), BufSize)
	return &Iost{Scanner: scanner, Writer: bufio.NewWriter(wfp)}
}
func (i *Iost) Text() string {
	if !i.Scanner.Scan() {
		panic("scan failed")
	}
	return i.Scanner.Text()
}
func (i *Iost) Atoi(s string) int                 { x, _ := strconv.Atoi(s); return x }
func (i *Iost) GetNextInt() int                   { return i.Atoi(i.Text()) }
func (i *Iost) Atoi64(s string) int64             { x, _ := strconv.ParseInt(s, 10, 64); return x }
func (i *Iost) GetNextInt64() int64               { return i.Atoi64(i.Text()) }
func (i *Iost) Atof64(s string) float64           { x, _ := strconv.ParseFloat(s, 64); return x }
func (i *Iost) GetNextFloat64() float64           { return i.Atof64(i.Text()) }
func (i *Iost) Print(x ...interface{})            { fmt.Fprint(i.Writer, x...) }
func (i *Iost) Printf(s string, x ...interface{}) { fmt.Fprintf(i.Writer, s, x...) }
func (i *Iost) Println(x ...interface{})          { fmt.Fprintln(i.Writer, x...) }
func isLocal() bool                               { return os.Getenv("WITHIN") == "TEMPTATION" }
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	if isLocal() {
		fp, _ = os.Open(os.Getenv("REMEMBER_YOU_AS_LONG_AS_I_CAN"))
	}
	iost = NewIost(fp, wfp)
	defer func() {
		iost.Writer.Flush()
	}()
	solve()
}
func solve() {
	SetMod(Mod998244353)
	n := iost.GetNextInt()
	aa := make([]int, n)
	for i := 0; i < n; i++ {
		aa[i] = iost.GetNextInt()
	}
	var ans Mint
	for i := 0; i < n-1; i++ {
		ans.AddAs(Mint(2).Pow(Mint(n - 1)).Sub(Mint(2).Pow(Mint(i))).Mul(Mint(aa[i])))
	}
	for i := 1; i < n; i++ {
		suf := n - (i + 1)
		ans.SubAs(Mint(2).Pow(Mint(n - 1)).Sub(Mint(2).Pow(Mint(suf))).Mul(Mint(aa[i])))
	}
	iost.Println(ans)
}

// Mod constants.
const (
	Mod1000000007 = 1000000007
	Mod998244353  = 998244353
)

var (
	mod  Mint
	fmod func(Mint) Mint
)

// Mint treats the modular arithmetic
type Mint int64

// SetMod sets the mod. It must be called first.
func SetMod(newmod Mint) {
	switch newmod {
	case Mod1000000007:
		fmod = staticMod1000000007
	case Mod998244353:
		fmod = staticMod998244353
	default:
		mod = newmod
		fmod = dynamicMod
	}
}
func dynamicMod(m Mint) Mint {
	m %= mod
	if m < 0 {
		return m + mod
	}
	return m
}
func staticMod1000000007(m Mint) Mint {
	m %= Mod1000000007
	if m < 0 {
		return m + Mod1000000007
	}
	return m
}
func staticMod998244353(m Mint) Mint {
	m %= Mod998244353
	if m < 0 {
		return m + Mod998244353
	}
	return m
}

// Mod returns m % mod.
func (m Mint) Mod() Mint {
	return fmod(m)
}

// Inv returns modular multiplicative inverse
func (m Mint) Inv() Mint {
	return m.Pow(Mint(0).Sub(2))
}

// Pow returns m^n
func (m Mint) Pow(n Mint) Mint {
	p := Mint(1)
	for n > 0 {
		if n&1 == 1 {
			p.MulAs(m)
		}
		m.MulAs(m)
		n >>= 1
	}
	return p
}

// Add returns m+x
func (m Mint) Add(x Mint) Mint {
	return (m + x).Mod()
}

// Sub returns m-x
func (m Mint) Sub(x Mint) Mint {
	return (m - x).Mod()
}

// Mul returns m*x
func (m Mint) Mul(x Mint) Mint {
	return (m * x).Mod()
}

// Div returns m/x
func (m Mint) Div(x Mint) Mint {
	return m.Mul(x.Inv())
}

// AddAs assigns *m + x to *m and returns m
func (m *Mint) AddAs(x Mint) *Mint {
	*m = m.Add(x)
	return m
}

// SubAs assigns *m - x to *m and returns m
func (m *Mint) SubAs(x Mint) *Mint {
	*m = m.Sub(x)
	return m
}

// MulAs assigns *m * x to *m and returns m
func (m *Mint) MulAs(x Mint) *Mint {
	*m = m.Mul(x)
	return m
}

// DivAs assigns *m / x to *m and returns m
func (m *Mint) DivAs(x Mint) *Mint {
	*m = m.Div(x)
	return m
}