A134770 interleaved with threes.

Terms

a(0) =1a(1) =3a(2) =5a(3) =3a(4) =21a(5) =3a(6) =77a(7) =3a(8) =277a(9) =3a(10) =1005a(11) =3a(12) =3693a(13) =3a(14) =13725a(15) =3a(16) =51477a(17) =3a(18) =194477a(19) =3a(20) =739021a(21) =3a(22) =2821725a(23) =3a(24) =10816621a(25) =3a(26) =41602397a(27) =3a(28) =160466397a(29) =3