A054229 Number of positive integers <= 2^n of form x^2 + 15 y^2.

1, 1, 2, 2, 5, 9, 16, 27, 52, 91, 173, 322, 606, 1152, 2191, 4191, 8060, 15540, 30018, 58161, 112891, 219479, 427440, 833615, 1627752, 3182068, 6226916, 12196740, 23910690, 46911434, 92104753, 180957883, 355748937, 699779680, 1377255678