Normalized triangle of odd numbered entries of even numbered rows of Pascal's triangle A007318.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =10a(5) =3a(6) =1a(7) =7a(8) =7a(9) =1a(10) =5a(11) =60a(12) =126a(13) =60a(14) =5a(15) =3a(16) =55a(17) =198a(18) =198a(19) =55a(20) =3a(21) =7a(22) =182a(23) =1001a(24) =1716a(25) =1001a(26) =182a(27) =7a(28) =1a(29) =35