a(n) = A047762(2n+1).

Terms

a(0) =0a(1) =0a(2) =1a(3) =6a(4) =32a(5) =176a(6) =952a(7) =5302a(8) =29960a(9) =172536a(10) =1007575a(11) =5959656a(12) =35622384a(13) =214875104a(14) =1306303424a(15) =7995896502a(16) =49236826080a(17) =304799714960