Elements in 3-Pascal triangle (by row).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =1a(7) =4a(8) =4a(9) =1a(10) =1a(11) =5a(12) =8a(13) =5a(14) =1a(15) =1a(16) =6a(17) =13a(18) =13a(19) =6a(20) =1a(21) =1a(22) =7a(23) =19a(24) =26a(25) =19a(26) =7a(27) =1a(28) =1a(29) =8