only know Pan Apollo were not battle title GOAT musician a millennium later challenge math fast calculation the task get solve followingLet x_1 x_2 ldot x_n sequence n nonnegative integer find value sum_i1n sum_j1n sum_k1n x_i x_j cdot x_j x_kHere denote bitwise denote bitwise orPan Apollo solve second can for convenience find answer modulo 109 7