With recursive increase as(

Select 1 as base

union all

select base+1 as base from increase where (base)<40 )

select LPAD('',base, '* ') from increase where mod(base,2)=0;

--This is my solution in Oracle SELECT LPAD('* ', LEVEL * 2, '* ') FROM DUAL CONNECT BY LEVEL <= 20;

WITH pattern AS ( SELECT 1 AS N UNION ALL SELECT N + 1 FROM pattern WHERE N < 20 ) SELECT REPLICATE(' *',N) FROM pattern OPTION (MAXRECURSION 0)

DECLARE @start_num INT, @end_num INT, @iterator INT, @pattern varchar(100) = '' SET @iterator = 1 SET @end_num = 20 -- Set to 20 for P(20)

WHILE @iterator <= @end_num BEGIN SET @start_num = 1 set @pattern = '' WHILE @start_num <= @iterator BEGIN set @pattern = @pattern + ' *' SET @start_num = @start_num + 1 END PRINT(@pattern) SET @iterator = @iterator + 1 END;

for MSSQL WITH pattern(n) AS ( SELECT 1 UNION ALL SELECT n + 1 FROM pattern WHERE n < 20 ) SELECT replicate('* ', n) FROM pattern;