%I #16 Nov 26 2017 21:49:57
%S 2,3,4,7,10,11,12,13,14,15,16,19,22,25,28,31,34,35,36,37,38,39,40,41,
%T 42,43,44,45,46,47,48,49,50,51,52,55,58,61,64,67,70,73,76,79,82,85,88,
%U 91,94,97,100,103,106,107,108,109,110,111,112,113,114,115,116,117,118,119
%N a(0) = 2; for n>0, a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) == 1 mod 3".
%D Hsien-Kuei Hwang, S Janson, TH Tsai, Exact and asymptotic solutions of the recurrence f(n) = f(floor(n/2)) + f(ceiling(n/2)) + g(n): theory and applications, Preprint, 2016; http://140.109.74.92/hk/wp-content/files/2016/12/aat-hhrr-1.pdf. Also Exact and Asymptotic Solutions of a Divide-and-Conquer Recurrence Dividing at Half: Theory and Applications, ACM Transactions on Algorithms, 13:4 (2017), #47; DOI: 10.1145/3127585
%H B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL6/Cloitre/cloitre2.html">Numerical analogues of Aronson's sequence</a>, J. Integer Seqs., Vol. 6 (2003), #03.2.2.
%H B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://arXiv.org/abs/math.NT/0305308">Numerical analogues of Aronson's sequence</a> (math.NT/0305308)
%H <a href="/index/Aa#aan">Index entries for sequences of the a(a(n)) = 2n family</a>
%F a(a(n)) = 3*n+4, n >= 0.
%o (PARI) {a=2; m=[2]; for(n=1,66,print1(a,","); a=a+1; if(a%3==1&&a==n,qwqw=qwqw,if(m==[], while(a%3!=1&&a==n,a++),if(m[1]==n, while(a%3!=1,a++); m=if(length(m) == 1,[],vecextract(m,"2..")),if(a%3==1,a++))); m=concat(m,a)))}
%Y Cf. A079000, A080720, ...
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_, Mar 08 2003
%E More terms and PARI code from _Klaus Brockhaus_, Mar 08 2003