3-Knödel numbers or D-numbers: numbers m > 3 such that m | k^(m-2)-k for all k with gcd(k, m) = 1.

Terms

a(0) =9a(1) =15a(2) =21a(3) =33a(4) =39a(5) =51a(6) =57a(7) =63a(8) =69a(9) =87a(10) =93a(11) =111a(12) =123a(13) =129a(14) =141a(15) =159a(16) =177a(17) =183a(18) =195a(19) =201a(20) =213a(21) =219a(22) =237a(23) =249a(24) =267a(25) =291a(26) =303a(27) =309a(28) =315a(29) =321