%I #61 Jan 11 2022 08:27:04
%S 1,2,4,6,9,14,22,33,49,74,112,169,254,381,573,862,1292,1936,2902,4352,
%T 6525,9788,14687,22028,33050,49576,74378,111579,167387,251089,376630,
%U 564931,847375,1271058,1906627,2859983,4289952,6434942,9652396
%N From substitutional generation of Kolakoski sequence (A000002).
%C Generate A000002 via 2 -> 22 -> 2211 -> 221121 -> 221121221 -> ...; sequence gives lengths of successive strings.
%C a(n) appears to be asymptotic to c*(3/2)^n where c=1.3094... - _Benoit Cloitre_, Dec 18 2002
%C A more accurate estimate is c=1.309346948, probably correct to one unit in the last place. - _Richard P. Brent_, Dec 30 2016
%H Richard P. Brent and Judy-anne H. Osborn, <a href="/A042942/b042942.txt">Table of n, a(n) for n = 1..100</a> (first 69 terms from David Spies)
%H Richard P. Brent and Judy-anne H. Osborn, <a href="https://maths-people.anu.edu.au/~brent/pd/Kolakoski-ACCMCC.pdf">A fast algorithm for the Kolakoski sequence</a>, Dec. 2016.
%H David Spies, <a href="/A042942/a042942.rs.txt">Rust program for generating terms</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/KolakoskiSequence.html">Kolakoski sequence</a>.
%F a(n) = A001083(n-2) - 1. - _Andrey Zabolotskiy_, Jan 10 2022
%Y Cf. A000002, A001083.
%K nonn,nice,easy
%O 1,2
%A _David W. Wilson_