--generate a sequence of digit from 0 to n
CREATE TABLE DBO.NUMBERS(i INT NOT NULL PRIMARY KEY);
go
INSERT INTO dbo.numbers(i)VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
go

INSERT INTO dbo.numbers(i)
SELECT num
from (
	SELECT (n4.i * 1000 + n3.i * 100 + n2.i * 10 + n1.i) AS num
	FROM dbo.numbers n1
	CROSS JOIN dbo.numbers n2
	CROSS JOIN dbo.numbers n3
	CROSS JOIN dbo.numbers n4	
) x
WHERE num > 9
ORDER BY num;

--goal: Output CombYr = 3/4/5/
--Input: @startYr int, @endYr int
--assume inputs are valid. and year is 4-digit format. and EndYr - BegYr <= 10
DECLARE @startYr INT = 2011
      , @endYr INT = 2013;
DECLARE @outputStr NVARCHAR(100) = '';
      
SELECT @outputStr = @outputStr +  RIGHT(CAST(n.i AS VARCHAR(4)), 1) + '/' 
FROM dbo.numbers n
WHERE n.i BETWEEN @startYr AND @endYr;

SELECT @outputStr;