a(n) = (1/2)*( (1 + (-1)^n)*A134760(n/2) + (1 - (-1)^n) ).

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =11a(5) =1a(6) =39a(7) =1a(8) =139a(9) =1a(10) =503a(11) =1a(12) =1847a(13) =1a(14) =6863a(15) =1a(16) =25739a(17) =1a(18) =97239a(19) =1a(20) =369511a(21) =1a(22) =1410863a(23) =1a(24) =5408311a(25) =1a(26) =20801199a(27) =1a(28) =80233199a(29) =1