Triangular array formed from odd elements to right of middle of rows of Pascal's triangle.

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =1a(5) =5a(6) =1a(7) =15a(8) =1a(9) =35a(10) =21a(11) =7a(12) =1a(13) =1a(14) =9a(15) =1a(16) =45a(17) =1a(18) =165a(19) =55a(20) =11a(21) =1a(22) =495a(23) =1a(24) =1287a(25) =715a(26) =13a(27) =1a(28) =3003a(29) =1001