-1,2

Rows of A164281 tend to A166242. Subsets of the first 2^n terms can be parsed into a binomial frequency of

powers of 2; for example, the first 16 terms has as frequency of

(1, 4, 6, 4, 1): (one 1, four 2's, six 4's, four 8's, and one 16.).

Let a(-1) = 1, then a(n+1) = 2*a(n) if A014577(n+1) = 1. If A014577(n+1) = 0, then a(n+1) = (1/2)*a(n).

As a recursive string in subsets of 2^n terms, the next subset = twice each term of current string, reversed, and appended.

From the Dragon curve, A014577:

...1...1...0...1...1...0...0...1... generates A166242:

1..2...4...2...4...8...4...2...4... given A166242(-1) = 1.

By recursion, given the first four terms: (1, 2, 4, 2); reverse, double, and

append to (1, 2, 4, 2) getting (1, 2, 4, 2, 4, 8, 4, 2,...).

A014577, A164281

Sequence in context: A047975 A112791 A143107 this_sequence A051638 A155682 A151706

Adjacent sequences: A166239 A166240 A166241 this_sequence A166243 A166244 A166245

nonn

Gary W. Adamson (qntmpkt(AT)yahoo.com), Oct 10 2009