{2n}_{2n}.

Terms

a(0) =2a(1) =4a(2) =6a(3) =8a(4) =10a(5) =14a(6) =18a(7) =22a(8) =26a(9) =40a(10) =46a(11) =52a(12) =58a(13) =64a(14) =90a(15) =98a(16) =106a(17) =114a(18) =122a(19) =160a(20) =170a(21) =180a(22) =190a(23) =200a(24) =250a(25) =262a(26) =274a(27) =286a(28) =298a(29) =360