<http://theculture.sg/2015/09/things-you-might-want-to-know-for-conjecture/#webpage>
<http://schema.org/description>
"1. $latex 2n$ is always even while $latex 2n \\pm 1$ is always odd. 2. $latex n!$ series, 1, 2, 6, 24, 120, 720, ... Be comfortable withholding and subtracting 1 from it too, for example 2, 3, 7, 25, 121, 721. 3. APGP Series. 4. $latex 2^n$ series, 2, 4, 8, 16, 32, 64,"
<http://theculture.sg/2015/09/things-you-might-want-to-know-for-conjecture/>