A077815 2^phi(n) mod n^2, where phi=A000010 (Euler's totient).

0, 2, 4, 4, 16, 4, 15, 16, 64, 16, 56, 16, 40, 64, 31, 0, 222, 64, 58, 256, 127, 56, 392, 256, 451, 40, 433, 176, 30, 256, 187, 0, 958, 800, 841, 208, 38, 780, 586, 1536, 944, 568, 1076, 1200, 91, 392, 2069, 1024, 2157, 1076, 1021, 1600, 1909, 2620, 826, 2752