Riordan matrix (1/(1-x-x^2-x^3),(x+x^2+x^3)/(1-x-x^2-x^3)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =1a(6) =4a(7) =8a(8) =5a(9) =1a(10) =7a(11) =19a(12) =18a(13) =7a(14) =1a(15) =13a(16) =43a(17) =54a(18) =32a(19) =9a(20) =1a(21) =24a(22) =94a(23) =147a(24) =117a(25) =50a(26) =11a(27) =1a(28) =44a(29) =200