a(n) = A047765(2n).

Terms

a(0) =0a(1) =1a(2) =2a(3) =2a(4) =7a(5) =12a(6) =29a(7) =55a(8) =143a(9) =271a(10) =728a(11) =1428a(12) =3873a(13) =7752a(14) =21318a(15) =43256a(16) =120175a(17) =246675a(18) =690678a(19) =1430715a(20) =4032015a(21) =8414610a(22) =23841480a(23) =50067108a(24) =142498637a(25) =300830572a(26) =859515920a(27) =1822766377a(28) =5225264024a(29) =11124755664