public function dataProviderForPowersOfTwo() { return [[-1, []], [0, []], [1, [1]], [2, [1, 2]], [3, [1, 2, 4]], [20, [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288]]]; }