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CREATE OR REPLACE FUNCTION f_ulam_do_sum( ulam int[] )
RETURNS SETOF int
AS $CODE$
DECLARE
left_index int;
right_index int;
BEGIN
FOR left_index IN 1 .. array_length( ulam, 1 ) LOOP
FOR right_index IN left_index + 1 .. array_length( ulam, 1 ) LOOP
RETURN NEXT ulam[ left_index ] + ulam[ right_index ];
END LOOP;
END LOOP;
RETURN;
END
$CODE$
LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION f_ulam( u int, v int, lim int default 10 )
RETURNS int[]
AS $CODE$
DECLARE
ulam int[];
next_value int;
BEGIN
-- PERFORM array_append( ulam, u );
-- PERFORM array_append( ulam, v );
-- PERFORM array_append( ulam, u + v );
ulam := ulam || u || v || u + v;
WHILE array_length( ulam, 1 ) < lim LOOP
SELECT vv
INTO next_value
FROM f_ulam_do_sum( ulam ) AS sums( vv )
WHERE vv > ulam[ array_length( ulam, 1 ) ]
GROUP BY 1
HAVING COUNT( * ) = 1
ORDER BY vv
LIMIT 1;
ulam := ulam || next_value;
END LOOP;
RETURN ulam;
END
$CODE$
LANGUAGE plpgsql;
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