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CREATE SCHEMA IF NOT EXISTS pwc154;
CREATE OR REPLACE FUNCTION
pwc154.padovan( i int )
RETURNS int
AS $CODE$
BEGIN
IF i <= 2 THEN
RETURN 1;
END IF;
RETURN pwc154.padovan( i - 3 ) + pwc154.padovan( i - 2 );
END
$CODE$
LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION
pwc154.is_prime( n int )
RETURNS bool
AS $CODE$
DECLARE
i int;
BEGIN
FOR i IN 2 .. n - 1 LOOP
IF n % i = 0 THEN
RETURN false;
END IF;
END LOOP;
RETURN true;
END
$CODE$
LANGUAGE plpgsql;
/**
p
----
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(10 rows)
*/
WITH
padovan AS (
SELECT n, pwc154.padovan( n ) AS p
FROM generate_series( 0, 50 ) n
)
, padovan_prime
AS (
SELECT p, pwc154.is_prime( p ) AS prime
FROM padovan p
)
SELECT distinct( p )
FROM padovan_prime
WHERE prime
ORDER BY 1
LIMIT 10
;
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