What is the format for the album under the label, luaka bop, that had a catalog number of 3645 and dated after 1981?
CREATE TABLE "release_history" (
  "region" text,
  "date" real,
  "label" text,
  "format" text,
  "catalog" text
);
SELECT "format" FROM "release_history" WHERE "catalog"='3645' AND "date">1981 AND "label"='luaka bop';