Generalized Lucas numbers.

Terms

a(0) =1a(1) =0a(2) =4a(3) =5a(4) =15a(5) =28a(6) =60a(7) =117a(8) =230a(9) =440a(10) =834a(11) =1560a(12) =2891a(13) =5310a(14) =9680a(15) =17527a(16) =31545a(17) =56468a(18) =100590a(19) =178395a(20) =315106a(21) =554530a(22) =972564a(23) =1700400a(24) =2964325a(25) =5153868a(26) =8938300a(27) =15465497a(28) =26700915a(29) =46004620