Even-numbered rows of Pascal's triangle.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =1a(5) =4a(6) =6a(7) =4a(8) =1a(9) =1a(10) =6a(11) =15a(12) =20a(13) =15a(14) =6a(15) =1a(16) =1a(17) =8a(18) =28a(19) =56a(20) =70a(21) =56a(22) =28a(23) =8a(24) =1a(25) =1a(26) =10a(27) =45a(28) =120a(29) =210