Odd numbers to left of central elements of the (3,2)-Pascal triangle A029618.

Terms

a(0) =3a(1) =3a(2) =3a(3) =3a(4) =11a(5) =3a(6) =3a(7) =17a(8) =3a(9) =57a(10) =3a(11) =23a(12) =77a(13) =147a(14) =3a(15) =3a(16) =29a(17) =3a(18) =155a(19) =3a(20) =35a(21) =187a(22) =605a(23) =3a(24) =1925a(25) =3a(26) =41a(27) =2717a(28) =5291a(29) =3