OFFSET
1,1
COMMENTS
The single 1's whose ranks are given by this sequence are the 1's between two 2's in the OK sequence A000002. They are associated with iterated words of the OK sequence that develop themselves around each single 1 in two branches (for a description of the iterated words, see comments in A249507, which gives their lengths). The first term of A000002, which is indeed a single 1 but not between two 2's, is thus not considered here.
Each such single 1 is generated by a preceding 1 in the OK sequence that could be single or double, but each single 1 has a double 1 in its ancestors since the first 1 of the OK sequence has no descendants except itself. The length of the iterated word around a single 1 is linked to the number of generations between itself and its nearest double 1 ancestor (A249949 gives the number of generations of the n-th single 1).
A249948 gives the gaps between single 1's.
LINKS
Jean-Christophe Hervé, Table of n, a(n) for n = 1..10000
FORMULA
CROSSREFS
KEYWORD
nonn
AUTHOR
Jean-Christophe Hervé, Nov 08 2014
STATUS
approved