Salesforce Custom State Field Validation:

OR( ISNUMBER( State__c ), OR(CONTAINS(State__c , "!"),CONTAINS(State__c , "@"),CONTAINS(State__c , "#"), CONTAINS(State__c , "$"),CONTAINS(State__c , "$"),CONTAINS(State__c , "%"),CONTAINS(State__c , "^"), CONTAINS(State__c , "&"),CONTAINS(State__c , "*"),CONTAINS(State__c , ","),CONTAINS(State__c , ":"),CONTAINS(State__c , ".") ,CONTAINS(State__c , "{"),CONTAINS(State__c , "}"),CONTAINS(State__c , "]"),CONTAINS(State__c , "["),CONTAINS(State__c , ";") ,CONTAINS(State__c , "="),CONTAINS(State__c , "+"),CONTAINS(State__c , "("),CONTAINS(State__c , ")"),CONTAINS(State__c , "_"),CONTAINS(State__c , "-"),CONTAINS(State__c , "|"),CONTAINS(State__c , "{"),CONTAINS(State__c , "}"),CONTAINS(State__c , "1"),CONTAINS(State__c , "2"),CONTAINS(State__c , "3"),CONTAINS(State__c , "4"),CONTAINS(State__c , "5"),CONTAINS(State__c , "6"),CONTAINS(State__c , "7"),CONTAINS(State__c , "8"),CONTAINS(State__c , "9"),CONTAINS(State__c , "0")))