%I
%S 5,8,10,9,11,11,11,11,8,11,11,11,11,11,11,11,11,11,11,11,11,11,20,16,
%T 41,31,28,28,31,54,21,9,36,11,24,23,32,10,37,42,12,27,46,16,40,27,6,
%U 19,45,13,42,42,37,61,37,98,93,18,44,33,19,59,35,54,166,131
%N Length of nth chain in A331440.
%H Lars Blomberg, <a href="/A331442/b331442.txt">Table of n, a(n) for n = 1..3000</a>
%H Rémy Sigrist, <a href="/A331442/a331442.gp.txt">PARI program for A331442</a>
%e When starting chain 9, A331440(77) is set to the first free number which is 17, and the chain becomes 17, 34, 68, 136, 272, 544, 1088, 2176 with length 8.
%o (PARI) See Links section.
%Y Cf. A331440, A331441.
%K nonn,base
%O 1,1
%A _N. J. A. Sloane_, Jan 22 2020
%E Corrected a(9) and more terms from _Lars Blomberg_, Jan 22 2020
