A024728 a(n) = s(n+3)/4, where s is A024727.

1, 1, 1, 5, 9, 13, 33, 73, 145, 313, 657, 1549, 3353, 7221, 16129, 36785, 81921, 180529, 403809, 939573, 2125193, 4756893, 10800801, 25195577, 57552721, 130500393, 298271153, 700076797, 1610366937, 3680601093, 8482477313, 19929303521