A078578 Euler's totient of the average of n-th twin prime pair.

2, 2, 4, 6, 8, 12, 16, 24, 32, 36, 44, 40, 48, 64, 60, 72, 64, 72, 92, 96, 112, 96, 144, 120, 168, 144, 160, 204, 212, 160, 216, 272, 264, 240, 252, 256, 336, 240, 348, 288, 384, 320, 420, 336, 360, 320, 384, 440, 432, 480, 528, 432, 552, 564, 480, 592, 576, 624