The solutions are the numbers such that or 1 (mod 4), excluding (Lossers 1998), giving 1, 5, 8, 9, 12, 13, 16, 17, ... (OEIS
A100832). For example, 5 and 8 are amenable
since
Lossers, O. P. "Solution to Problem 10454. Amenable Numbers." Amer. Math. Monthly105, 1998.Sloane, N. J. A.
Sequence A100832 in "The On-Line Encyclopedia
of Integer Sequences."Tamvakis, H. "Problem 10454." Amer.
Math. Monthly102, 463, 1995.