Odd-numbered rows of Pascal's triangle.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =3a(5) =1a(6) =1a(7) =5a(8) =10a(9) =10a(10) =5a(11) =1a(12) =1a(13) =7a(14) =21a(15) =35a(16) =35a(17) =21a(18) =7a(19) =1a(20) =1a(21) =9a(22) =36a(23) =84a(24) =126a(25) =126a(26) =84a(27) =36a(28) =9a(29) =1