check if an NSString contains 4 consecutive numbers --- IOS

- (BOOL)isSequence:(NSString *)string

{

    

    NSArray *arr = [NSArray arrayWithObjects:@"1234",@"2345",@"3456",@"4567",@"5678",@"6789",  nil];

    

    BOOL found=NO;

    for (NSString *s in arr)

    {

        if ([string rangeOfString:s].location != NSNotFound) {

            NSLog(@"found");

            found = YES;

            break;

        }

    }