Nonprime Lucas numbers.

Terms

a(0) =1a(1) =4a(2) =18a(3) =76a(4) =123a(5) =322a(6) =843a(7) =1364a(8) =5778a(9) =15127a(10) =24476a(11) =39603a(12) =64079a(13) =103682a(14) =167761a(15) =271443a(16) =439204a(17) =710647a(18) =1149851a(19) =1860498a(20) =4870847a(21) =7881196a(22) =12752043a(23) =20633239a(24) =33385282a(25) =87403803a(26) =141422324a(27) =228826127a(28) =599074578a(29) =969323029