56732domain: NAppears in sequencesNumbers k such that sigma(k) = sigma(k+13).at n=16A015883Number of -2..2 arrays x(0..n-1) of n elements with sum zero and with zeroth through n-1st differences all nonzero.at n=11A200032p-INVERT of the positive integers, where p(S) = 1 - 4*S + 3*S^2.at n=6A291184