[seqfan] A135282: We can go ahead and change "seems" to "is known"

[Alonso Del Arte]

"It seems all terms are even,unless n is odd power of 2"

Besides punctuation, I think we can also go ahead and change "seems" to "is
known that." If you'll forgive the use of the equals sign as a congruence
sign,

2 = -1 mod 3

2 * 2 = -1 * -1 = 1 mod 3

Therefore, only even-indexed powers of 2 are congruent to 1 mod 3 and thus
reachable by either a halving step or a "tripling step," whereas the
odd-indexed powers of 2 are only reachable by a halving step—or as an
initial value.

Al