seq: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/seq - from package: coreutils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/seq - from package: coreutils
/usr/lib/plan9/bin/seq - from package: 9base

You may install the required package with command apt-get install {package}

Error in other languages:
seq: bevel nie gevind nie
seq: comandă negăsită
seq: comando não encontrado
seq: commande introuvable
seq: command not found
seq: käsku ei ole
seq: không tìm thấy lệnh
seq: komanda nerasta
seq: Kommando nicht gefunden.
seq: kommandot finns inte
seq: komut yok
seq: nie znaleziono polecenia
seq: níor aimsíodh an t-ordú
seq: no se encontró la orden
seq: no s'ha trobat l'ordre
seq: opdracht niet gevonden
seq: parancs nem található
seq: perintah tidak ditemukan
seq: príkaz nenájdený
seq: příkaz nenalezen
seq: команда не найдена
seq: командата не е открита
seq: 命令找不到
seq: コマンドが見つかりません