A054173 Number of positive integers <= 2^n of form 4 x^2 + 9 y^2.

0, 0, 1, 1, 4, 5, 10, 18, 35, 65, 120, 225, 430, 814, 1549, 2981, 5739, 11084, 21474, 41663, 81033, 157830, 307912, 601482, 1176314, 2302911, 4513106, 8851907, 17376317, 34134944, 67101922, 131990741, 259779732, 511566355, 1007901666