Pascal-like triangle associated with A000670.

Terms

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