Error with SQL SERVER sequences

When trying to create a sequence in my database, I get an error. Then proceed to publish the script and the error of the query:

create sequence seq_valorar
start with 300
increment by 1
minvalue 300
no maxvalue 
no cycle;

create sequence seq_val
start with 300
increment by 1
minvalue 300
no maxvalue 
no cycle;

  

SQL error (343): Unknown object type 'sequence' used in a CREATE, DROP or ALTER statement